Physical activity, sedentary behaviors, physical fitness, and their relation to health outcomes in youth with type 1 and type 2 diabetes:A review of the epidemiologic literature

Diabetes is a leading chronic disease of childhood and adolescence. In addition to the well-known auto-immune, insulin-dependent diabetes mellitus (type 1 diabetes (T1D)), the past two decades have witnessed the emergence of type 2 diabetes (T2D) in children and adolescents, which previously was only seen in middle-aged or older adults. One of the key components of diabetes management is physical activity (PA). The beneficial effects of increased PA and decreased sedentary behavior are extremely important in youth with diabetes because of the markedly increased long-term risk of cardiovascular disease in this population compared to persons without diabetes. This review aims to comprehensively summarize the epidemiologic, observational research published and listed in PubMed between 1970 and 2012 on PA and sedentary behaviors, as well as physical fitness in children and adolescents with T1D and T2D. Additionally, we describe briefly the state of knowledge on perceived barriers of PA in persons with diabetes, with a focus on hypoglycemia. Finally, we provide an overview of the epidemiological literature pertaining to health benefits of increased PA in youth with T1D and T2D and briefly discuss the topic of exercise-related hypoglycemia.

Related papers:

title: Incidence of diabetes in youth in the United States.
abstract: Data on the incidence of diabetes mellitus (DM) among US youth according to racial/ethnic background and DM type are limited.



To estimate DM incidence in youth aged younger than 20 years according to race/ethnicity and DM type.



A multiethnic, population-based study (The SEARCH for Diabetes in Youth Study) of 2435 youth with newly diagnosed, nonsecondary DM in 2002 and 2003, ascertained at 10 study locations in the United States, covering a population of more than 10 million person-years.



Incidence rates by age group, sex, race/ethnicity, and DM type were calculated per 100,000 person-years at risk. Diabetes mellitus type (type 1/type 2) was based on health care professional assignment and, in a subset, further characterized with glutamic acid decarboxylase (GAD65) autoantibody and fasting C peptide measures.



The incidence of DM (per 100,000 person-years) was 24.3 (95% confidence interval [CI], 23.3-25.3). Among children younger than 10 years, most had type 1 DM, regardless of race/ethnicity. The highest rates of type 1 DM were observed in non-Hispanic white youth (18.6, 28.1, and 32.9 for age groups 0-4, 5-9, and 10-14 years, respectively). Even among older youth (> or =10 years), type 1 DM was frequent among non-Hispanic white, Hispanic, and African American adolescents. Overall, type 2 DM was still relatively infrequent, but the highest rates (17.0 to 49.4 per 100,000 person-years) were documented among 15- to 19-year-old minority groups.



Our data document the incidence rates of type 1 DM among youth of all racial/ethnic groups, with the highest rates in non-Hispanic white youth. Overall, type 2 DM is still relatively infrequent; however, the highest rates were observed among adolescent minority populations.

title: Prevalence of overweight and obesity in youth with diabetes in USA: the SEARCH for Diabetes in Youth Study
abstract: Liu LL, Lawrence JM, Davis C, Liese AD, Pettitt DJ, Pihoker C, Dabelea D, Hamman R, Waitzfelder B, Kahn HS. Prevalence of overweight and obesity in youth with diabetes in USA: the SEARCH for Diabetes in Youth Study.

title: Prevalence of Cardiovascular Disease Risk Factors in U.S. Children and Adolescents With Diabetes
abstract: The purpose of this study was to determine the prevalence and correlates of selected cardiovascular disease (CVD) risk factors among youth aged <20 years with diabetes. The analysis included 1,083 girls and 1,013 boys examined as part of the SEARCH for Diabetes in Youth study, a multicenter, population-based study of youth 0–19 years of age with diabetes. Diabetes type was determined by a biochemical algorithm based on diabetes antibodies and fasting C-peptide level. CVD risk factors were defined as follows: HDL cholesterol <40 mg/dl; age- and sex-specific waist circumference >90th percentile; systolic or diastolic blood pressure >90th percentile for age, sex, and height or taking medication for high blood pressure; and triglycerides >110 mg/dl. The prevalence of having at least two CVD risk factors was 21%. The prevalence was 7% among children aged 3–9 years and 25% in youth aged 10–19 years (P < 0.0001), 23% among girls and 19% in boys (P = 0.04), 68% in American Indians, 37% in Asian/Pacific Islanders, 32% in African Americans, 35% in Hispanics, and 16% in non-Hispanic whites (P < 0.0001). At least two CVD risk factors were present in 92% of youth with type 2 and 14% of those with type 1A diabetes (P < 0.0001). In multivariate analyses, age, race/ethnicity, and diabetes type were independently associated with the odds of having at least two CVD risk factors (P < 0.0001). Many youth with diabetes have multiple CVD risk factors. Recommendations for weight, lipid, and blood pressure control in youth with diabetes need to be followed to prevent or delay the development of CVD as these youngsters mature.

title: Lipid abnormalities are prevalent in youth with type 1 and type 2 diabetes: the SEARCH for Diabetes in Youth Study.
abstract: Assessment of the prevalence of serum lipid abnormalities in US youth with type 1 or type 2 diabetes.



The SEARCH for Diabetes in Youth Study was a cross-sectional, population-based study, conducted in six centers. Subjects were 2448 youth with diabetes who had a study examination. Outcome measures were fasting measures of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, and non-HDL-C. Analysis was descriptive.



The overall prevalence of high TC concentration (>240 mg/dL) was 5%; the overall prevalence of high LDL-C (>160 mg/dL) was 3%, and the overall prevalence of high triglyceride (>400 mg/dL) was 2%. About half of the participants (48%) had an LDL-C concentration above the optimal level of 100 mg/dL. Among youth ages 10+, the prevalence of abnormal lipids was higher in type 2 (n = 283) than in type 1 diabetes (n = 1963): 33% versus 19% had TC concentration >200 mg/dL; 24% versus 15% had LDL-C concentration >130 mg/dL; 29% versus 10% had triglyceride concentration >150 mg/dL; 44% versus 12% had HDL-C concentration <40 mg/dL. Only 1% of youth were receiving pharmacologic therapy for dyslipidemia.



A substantial proportion of young patients with diabetes have abnormal serum lipids.

title: Care of children and adolescents with type 1 diabetes: a statement of the American Diabetes Association.
abstract: During recent years, the American Diabetes Association (ADA) has published detailed guidelines and recommendations for the management of diabetes in the form of technical reviews, position statements, and consensus statements. Recommendations regarding children and adolescents have generally been included as only a minor portion of these documents. For example, the most recent ADA position statement on “Standards of Medical Care for Patients With Diabetes Mellitus” (last revised October 2003) included “special considerations” for children and adolescents (1). Other position statements included age-specific recommendations for screening for nephropathy (2) and retinopathy (3) in children with diabetes. In addition, the ADA has published guidelines pertaining to certain aspects of diabetes that apply exclusively to children and adolescents, including care of children with diabetes at school (4) and camp (5) and a consensus statement on type 2 diabetes in children and adolescents (6).

The purpose of this document is to provide a single resource on current standards of care pertaining specifically to children and adolescents with type 1 diabetes. It is not meant to be an exhaustive compendium on all aspects of the management of pediatric diabetes. However, relevant references are provided and current works in progress are indicated as such. The information provided is based on evidence from published studies whenever possible and, when not, supported by expert opinion or consensus (7). Several excellent detailed guidelines and chapters on type 1 diabetes in pediatric endocrinology texts exist, including those by the International Society of Pediatric and Adolescent Diabetes (ISPAD) (8), by the Australian Pediatric Endocrine Group (www.chw.edu/au/prof/services/endocrinology/apeg), in Lifshitz’s Pediatric Endocrinology (9–11), and by Plotnick and colleagues (12,13).

Children have characteristics and needs that dictate different standards of care. The management of diabetes in children must take the major differences between children of various ages and …

title: How much physical activity should we do? The case for moderate amounts and intensities of physical activity.
abstract: A sedentary and unfit way of life leads to increased risk for several chronic diseases and premature mortality. Sedentary and unfit individuals are also more likely to develop functional limitations as they age. The precise type, amount, and intensity of physical activity required for protection needs further investigation. Traditional exercise recommendations suggest a threshold of activity that is necessary for protection, although current evidence does not support a dichotomous view of this issue. Clinical and epidemiological studies show a continuous dose-response gradient of outcome variables across a wide range of activity or fitness levels. Moderate amounts and intensities of physical activity are associated with improved health and reduced risk of morbidity and mortality when compared with low activity or fitness. The major public health emphasis for physical activity recommendations and programming should be to encourage the most sedentary and unfit 20 to 25% of the population to become at least moderately active, and this can yield substantial benefits for the population.

title: The Importance of Physical Activity and Cardiorespiratory Fitness for Patients With Type 2 Diabetes
abstract: In Brief Physical inactivity and low cardiorespiratory fitness increase the risk of developing type 2 diabetes and are associated with higher rates of cardiovascular disease and mortality in people with type 2 diabetes. Clinicians are encouraged to promote adoption of the consensus public health recommendation for physical activity for their sedentary and unfit patients and to stress that the benefit is improved health—not necessarily weight loss. Recent advances in behavioral intervention approaches can make clinicians more successful in helping their sedentary patients become and stay more physically active.

title: Physical fitness and all-cause mortality. A prospective study of healthy men and women.
abstract: We studied physical fitness and risk of all-cause and cause-specific mortality in 10,224 men and 3120 women who were given a preventive medical examination. Physical fitness was measured by a maximal treadmill exercise test. Average follow-up was slightly more than 8 years, for a total of 110,482 person-years of observation. There were 240 deaths in men and 43 deaths in women. Age-adjusted all-cause mortality rates declined across physical fitness quintiles from 64.0 per 10,000 person-years in the least-fit men to 18.6 per 10,000 person-years in the most-fit men (slope, -4.5). Corresponding values for women were 39.5 per 10,000 person-years to 8.5 per 10,000 person-years (slope, -5.5). These trends remained after statistical adjustment for age, smoking habit, cholesterol level, systolic blood pressure, fasting blood glucose level, parental history of coronary heart disease, and follow-up interval. Lower mortality rates in higher fitness categories also were seen for cardiovascular disease and cancer of combined sites. Attributable risk estimates for all-cause mortality indicated that low physical fitness was an important risk factor in both men and women. Higher levels of physical fitness appear to delay all-cause mortality primarily due to lowered rates of cardiovascular disease and cancer.

title: Physical activity in the United States measured by accelerometer.
abstract: To describe physical activity levels of children (6-11 yr), adolescents (12-19 yr), and adults (20+ yr), using objective data obtained with accelerometers from a representative sample of the U.S. population.



These results were obtained from the 2003-2004 National Health and Nutritional Examination Survey (NHANES), a cross-sectional study of a complex, multistage probability sample of the civilian, noninstitutionalized U.S. population in the United States. Data are described from 6329 participants who provided at least 1 d of accelerometer data and from 4867 participants who provided four or more days of accelerometer data.



Males are more physically active than females. Physical activity declines dramatically across age groups between childhood and adolescence and continues to decline with age. For example, 42% of children ages 6-11 yr obtain the recommended 60 min x d(-1) of physical activity, whereas only 8% of adolescents achieve this goal. Among adults, adherence to the recommendation to obtain 30 min x d(-1) of physical activity is less than 5%.



Objective and subjective measures of physical activity give qualitatively similar results regarding gender and age patterns of activity. However, adherence to physical activity recommendations according to accelerometer-measured activity is substantially lower than according to self-report. Great care must be taken when interpreting self-reported physical activity in clinical practice, public health program design and evaluation, and epidemiological research.

title: What are the health benefits of physical activity in type 1 diabetes mellitus? A literature review
abstract: Physical activity improves well-being and reduces the risk of heart disease, cancer and type 2 diabetes mellitus in the general population. In individuals with established type 2 diabetes, physical activity improves glucose and lipid levels, reduces weight and improves insulin resistance. In type 1 diabetes mellitus, however, the benefits of physical activity are less clear. There is poor evidence for a beneficial effect of physical activity on glycaemic control and microvascular complications, and significant risk of harm through hypoglycaemia. Here we review the literature relating to physical activity and health in type 1 diabetes. We examine its effect on a number of outcomes, including glycaemic control, lipids, blood pressure, diabetic complications, well-being and overall mortality. We conclude that whilst there is sufficient evidence to recommend physical activity in the management of type 1 diabetes, it is still unclear as to what form, duration and intensity should be recommended and whether there is benefit for many of the outcomes examined.

title: Physical activity is independently associated with multiple measures of arterial stiffness in adolescents and young adults.
abstract: Physical activity (PA) is associated with decreased levels of arterial stiffness in adults, but the relationship between PA and multiple measures of arterial stiffness in adolescents and young adults is not clear. The objective of this study was to test the hypothesis that PA is an independent predictor of multiple measures of arterial stiffness in adolescents and young adults. A total of 548 participants were enrolled in a study of the cardiovascular effects of obesity and type 2 diabetes mellitus (T2DM) (lean, 201; obese, 191; T2DM, 156). Anthropometrics, blood pressure, central and peripheral measures of arterial stiffness (pulse wave velocity, brachial distensibility, and augmentation index), blood (lipids and metabolic tests), and accelerometry data were collected. General linear modeling was performed to test for the independent relationship of PA on arterial stiffness. The mean age of the participants was 17.9 years (standard deviation, 3.5 years). After adjusting for other cardiovascular disease risk factors such as age, sex, body size, mean arterial pressure, and the presence of obesity or T2DM, PA was an independent predictor of augmentation index and brachial distensibility (P < .001). A greater effect of PA on pulse wave velocity was found in participants with T2DM (P = .009) compared with participants in the lean or obese groups. Physical activity is significantly and independently associated with multiple measures of arterial stiffness in adolescents and young adults. The role of PA in the prevention of cardiovascular disease target organ damage in youth, independent of energy balance, merits further exploration.

title: Mortality from heart disease in a cohort of 23,000 patients with insulin-treated diabetes
abstract: ischaemic heart disease is the predominant cause of mortality in older people with diabetes, age-specific mortality rates have not been published for patients with Type 1 diabetes. The Diabetes UK cohort, essentially one of patients with Type 1 diabetes, now has sufficient follow-up to report all heart disease, and specifically ischaemic heart disease, mortality rates by age.MethodsA cohort of 23,751 patients with insulin-treated diabetes, diagnosed under the age of 30 years and from throughout the United Kingdom, was identified during the period 1972 to 1993 and followed for mortality until December 2000. Age- and sex-specific heart disease mortality rates and standardised mortality ratios were calculated.ResultsThere were 1437 deaths during the follow-up, 536 from cardiovascular disease, and of those, 369 from ischaemic heart disease. At all ages the ischaemic heart disease mortality rates in the cohort were higher than in the general population. Mortality rates within the cohort were similar for men and women under the age of 40. The standardised mortality ratios were higher in women than men at all ages, and in women were 44.8 (95%CI 20.5–85.0) at ages 20–29 and 41.6 (26.7–61.9) at ages 30–39.Conclusions/interpretationThe risk of mortality from ischaemic heart disease is exceptionally high in young adult women with Type 1 diabetes, with rates similar to those in men with Type 1 diabetes under the age of 40. These observations emphasise the need to identify and treat coronary risk factors in these young patients.

title: Associations between physical activity, sedentary behavior, and glycemic control in a large cohort of adolescents with type 1 diabetes: the Hvidoere Study Group on Childhood Diabetes
abstract: The Hvidoere Study Group on Childhood Diabetes has demonstrated persistent differences in metabolic outcomes between pediatric diabetes centers. These differences cannot be accounted for by differences in demographic, medical, or treatment variables. Therefore, we sought to explore whether differences in physical activity or sedentary behavior could explain the variation in metabolic outcomes between centers.

title: Associations Between Media Consumption Habits, Physical Activity, Socioeconomic Status, and Glycemic Control in Children, Adolescents, and Young Adults With Type 1 Diabetes
abstract: To evaluate the relationship between media consumption habits, physical activity, socioeconomic status, and glycemic control in youths with type 1 diabetes.  In the cross-sectional study, self-report questionnaires were used to assess media consumption habits, physical activity, and socioeconomic status in 296 children, adolescents, and young adults with type 1 diabetes. Clinical data and HbA1c levels were collected. Risk factors were analyzed by multiple regression.  Youths with type 1 diabetes (aged 13.7 ± 4.1 years, HbA1c 8.7 ± 1.6%, diabetes duration 6.1 ± 3.3 years) spent 2.9 ± 1.8 h per day watching television and using computers. Weekly physical activity was 5.1 ± 4.5 h. Multiple regression analysis identified diabetes duration, socioeconomic status, and daily media consumption time as significant risk factors for glycemic control.  Diabetes duration, socioeconomic status, and daily media consumption time, but not physical activity, were significant risk factors for glycemic control in youths with type 1 diabetes.

title: Impact of Physical Activity on Cardiovascular Risk Factors in Children With Type 1 Diabetes
abstract: Type 1 diabetes is associated with a high risk for early atherosclerotic complications. Patients with type 1 diabetes have a fourfold (in men) to eightfold (in women) excess risk of coronary heart disease compared with that for the general population (1). It has been shown that type 1 diabetic patients aged 20–39 years have a fivefold higher risk of dying from cardio- and cerebrovascular events compared with that for healthy individuals (2). Development of atherosclerotic lesions in healthy subjects begins upon childhood. In children with type 1 diabetes who had died an unnatural death, an asymptomatic increase in the intima-media thickness of the common carotid artery was found (3). Known risk factors for vascular complications are long-standing diabetes, age, poor glycemic control, smoking, hypertension, obesity, and dyslipidemia (4–6). In a recent study, 69% of the pediatric patients with type 1 diabetes were found to have one or more cardiovascular risk factors (7). Thus, there is an urgent need for prevention strategies to reduce these risk factors in childhood and adolescence.

We recently showed that frequency of regular physical activity (RPA) represents an important factor influencing glycohemoglobin and, in girls, BMI (8). The present study focuses on the impact of RPA on further cardiovascular risk factors such as plasma lipids and blood pressure in children with type 1 diabetes.

Data were provided by the Pediatric Quality Initiative (9) and included anonymous longitudinal data of 23,251 patients (3–18 years) with type 1 diabetes from 209 centers in Germany and Austria. The data are continuously generated by the participating centers using the diabetes data acquisition system for prospective surveillance [DPV] software (Diabetes Software for Prospective Documentation) and after anonymization are transmitted to the Pediatric Quality Initiative for …

title: Effects of regular physical activity on control of glycemia in pediatric patients with type 1 diabetes mellitus.
abstract: To evaluate the effect of regular physical activity (RPA) on the control of glycemia (glycosylated hemoglobin A(1c) level) and the frequency of severe hypoglycemia in a large cohort of patients with type 1 diabetes mellitus.



Cross-sectional analysis of data for 19 143 patients, comparing control of glycemia and rate of hypoglycemia by frequency of RPA.



One hundred seventy-nine pediatric diabetes clinics in Germany and Austria.



Patients aged 3 to 20 years with type 1 diabetes mellitus.  Patients were grouped by the frequency of RPA per week as follows: RPA0, none; RPA1, 1 or 2 times per week; and RPA2, 3 or more times per week.



Glycosylated hemoglobin A(1c) level, body mass index (calculated as weight in kilograms divided by the square of height in meters) z score, and frequency of severe hypoglycemia.



Glycosylated hemoglobin A(1c) level was higher in the groups with less frequent RPA (8.4% in group RPA0 vs 8.1% in group RPA2; P<.001). This effect was found in both sexes and in all age groups (P<.001). In female patients but not in male patients, the body mass index z score decreased from 0.60 in group RPA0 to 0.51 in group RPA2 (P<.001). Multiple regression analysis revealed that RPA was one of the most important factors influencing the glycosylated hemoglobin level. No association was noted between frequency of RPA and frequency of severe hypoglycemia or hypoglycemia with loss of consciousness or seizure.



In pediatric patients with type 1 diabetes mellitus, frequency of RPA is a major factor influencing the control of glycemia without increasing the risk for severe hypoglycemia. Regular physical activity should be recommended in pediatric patients with type 1 diabetes mellitus.

title: Self-Management Behaviors, Racial Disparities, and Glycemic Control Among Adolescents With Type 2 Diabetes
abstract: Type 2 diabetes is a growing problem among adolescents, but little is known about self-management behaviors in this population. Our aim was to examine self-management behaviors and glycemic control among adolescents with type 2 diabetes.  From 2003 to 2005, a telephone survey of adolescents with type 2 diabetes was performed. Chart review obtained most recent glycated hemoglobin and clinical characteristics. Analyses compared patient characteristics and self-management behaviors to recent glycated hemoglobin levels.  Of 139 patients contacted, 103 (74%) completed the study. The mean age was 15.4 years: 69% were girls, 47% were white, and 46% were black. Mean glycated hemoglobin was 7.7%, and the average duration of diabetes was 2.0 years. More than 80% of patients reported ≥75% medication compliance, and 59% monitored blood glucose >2 times daily. However, patients reported frequent episodes of overeating, drinking sugary drinks, and eating fast food. More than 70% of patients reported exercising ≥2 times a week, but 68% reported watching ≥2 hours of television daily. Nonwhite patients had higher glycated hemoglobin and hospitalizations per year compared with white patients. In multivariable analyses, nonwhite race remained significantly associated with higher glycated hemoglobin even after adjusting for age, gender, BMI, insurance status, and other factors. Nonwhite patients were more likely to watch ≥2 hours of television per day (78% vs 56%), to report exercising ≤1 time per week (35% vs 21%), and to drink ≥1 sugary drink daily (27% vs 13%).  Although patients reported good medication and monitoring adherence, they also reported poor diet and exercise habits and multiple barriers. Nonwhite race was significantly associated with poorer glycemic control even after adjusting for covariates. This may, in part, be related to disparities in lifestyle behaviors. Additional studies are indicated to further assess self-management behaviors and potential racial disparities in adolescents with type 2 diabetes.

title: Physical Activity in Adolescent Females with Type 1 Diabetes
abstract: We sought to identify amount of physical activity and relationship of physical activity to glycemic control among adolescent females 11 to 19 years of age with type 1 diabetes mellitus (T1DM). We also sought to evaluate associations of age and ethnicity with physical activity levels.  Adolescent females ages 11–19 years (n = 203) were recruited during their outpatient diabetes appointment. Physical activity was obtained by self-report and was categorized as the number of days subjects had accumulated 60 minutes of moderate-to-vigorous physical activity during the past 7 days and for a typical week.  Girls reported being physically active for at least 60 minutes per day on 2.7 ± 2.3 days in the last week, and on 3.1 ± 2.2 days in a typical week. A greater number of physically active days in a typical week were associated with lower A1c (P = .049) in linear regression analysis.  Adolescent females with T1DM report exercising for at least 60 minutes about 3 days per week, which does not meet the international recommendations of 60 minutes of moderate-to-vigorous activity per day. It is particularly important that adolescent girls with T1DM be encouraged to exercise since a greater number of physically active days per week is associated with better glycemic control.

title: Physical activity and sports participation in children and adolescents with type 1 diabetes mellitus.
abstract: Regular physical activity is of great importance in the management of type 1 diabetes mellitus (T1DM). We investigate here the levels of moderate/vigorous physical activity (MVPA) and participation in sporting activity in a sample of children and adolescents with T1DM and analyse whether they differed from healthy subjects. The family variables associated with MVPA or sports participation and the influence of exercise on metabolic parameters are also explored.



In this cross-sectional case control study, 138 children and adolescents with T1DM (of which 67 were boys, age 13.6+/-4.1 years; duration of diabetes 6.1+/-3.8 years) and 269 (of which 120 were boys) healthy controls were studied. Weekly levels of MVPA and sports participation were investigated using a questionnaire. Body mass index standard deviation score (BMI-SDS) values, plasma total cholesterol, serum triglycerides and the mean glycated haemoglobin (A1c) levels over the past year were assessed in T1DM subjects. MVPA scores in T1DM patients were lower than in controls (p=0.0004). MVPA was higher in boys than in girls, both in diabetic and control subjects; T1DM girls were less frequently engaged in MVPA than control girls. MVPA scores were significantly and independently correlated with sex, age and diabetic status. Lower triglyceride levels and fewer subjects with poor metabolic control were found more among physically active patients (MVPA>5 days/week) than in inactive patients (weekly MVPA=0). Sports participation was lower in T1DM patients than in controls (p=0.002) and was significantly and independently correlated with sex, father's education level and diabetic status. Triglyceride levels and the percentage of subjects with poor metabolic control were significantly lower in sports participants than in non-participants.



Children and adolescents with T1DM appeared to spend less time in physical activity than their non-diabetic peers. Regular physical activity was associated with better metabolic control and lipid profile. Adolescents, particularly the girls, tended to be less active. Further efforts should be made to motivate patients with type 1 diabetes.

title: Outpatient assessment of determinants of glucose excursions in adolescents with type 1 diabetes: proof of concept.
abstract: Controlled inpatient studies on the effects of food, physical activity (PA), and insulin dosing on glucose excursions exist, but such outpatient data are limited. We report here outpatient data on glucose excursions and its key determinants over 5 days in 30 adolescents with type 1 diabetes (T1D) as a proof-of-principle pilot study.



Subjects (20 on insulin pumps, 10 receiving multiple daily injections; 15±2 years old; diabetes duration, 8±4 years; hemoglobin A1c, 8.1±1.0%) wore a continuous glucose monitor (CGM) and an accelerometer for 5 days. Subjects continued their existing insulin regimens, and time-stamped insulin dosing data were obtained from insulin pump downloads or insulin pen digital logs. Time-stamped cell phone photographs of food pre- and post-consumption and food logs were used to augment 24-h dietary recalls for Days 1 and 3. These variables were incorporated into regression models to predict glucose excursions at 1-4 h post-breakfast.



CGM data on both Days 1 and 3 were obtained in 57 of the possible 60 subject-days with an average of 125 daily CGM readings (out of a possible 144). PA and dietary recall data were obtained in 100% and 93% of subjects on Day 1 and 90% and 100% of subjects on Day 3, respectively. All of these variables influenced glucose excursions at 1-4 h after waking, and 56 of the 60 subject-days contributed to the modeling analysis.



Outpatient high-resolution time-stamped data on the main inputs of glucose variability in adolescents with T1D are feasible and can be modeled. Future applications include using these data for in silico modeling and for monitoring outpatient iterations of closed-loop studies, as well as to improve clinical advice regarding insulin dosing to match diet and PA behaviors.

title: Physical Activity and Electronic Media Use in the SEARCH for Diabetes in Youth Case-Control Study
abstract: The aim of this study was to characterize the physical activity (PA) and electronic media (EM) use habits of a population-based, ascertained sample of youths with diabetes mellitus (DM).  For this investigation, the Search for Diabetes in Youth Case-Control study (age: 10–20 y; 55% female) recruited 384 youths with provider-diagnosed type 1 DM, 90 youths with type 2 DM, and 173 healthy control subjects between 2003 and 2006, in 2 US centers. PA and EM use were assessed with a 3-day recall of activities, in 30-minute time blocks. Adherence to current recommendations was determined as a report of ≥2 blocks of moderate/vigorous PA per day and <4 blocks of EM use per day. Differences in PA and EM use for DM/control groups were assessed with adjustment for age, study site, and race/ethnicity.  Male subjects with type 2 DM reported lower levels of vigorous PA than did control subjects (1.1 vs 2.3 blocks; P < .05). Compliance with the moderate/vigorous PA recommendation among youths with type 2 DM was lower (68.3%), compared with youths with type 1 DM (81.7%; odds ratio: 0.51 [95% confidence interval: 0.26–1.00]; P = .047) and control subjects (80.4%; odds ratio: 0.48 [95% confidence interval: 0.23–1.02]; P = .05). Rates of compliance with EM use recommendations ranged from 29.5% to 49.1%.  In this study, large proportions of youths with DM, especially type 2 DM, failed to meet PA and EM use recommendations.

title: Cardiovascular fitness and quality of life in adolescents with type 1 or type 2 diabetes.
abstract: This descriptive study of adolescents with type 1 or type 2 diabetes examined the relationships between cardiovascular fitness and physical activity (PA) with generic or health-related quality of life (QoL), glycemic control, and lipids.



Graded ergometry testing for fitness, fasting assays for lipids, glycosylated hemoglobin (A1C), and self-reported PA and QoL instruments were completed with 151 adolescents.



Adolescents with type 2 diabetes had lower fitness. Fitness was associated with improved lipids, A1C, health perception, and athletic competence in adolescents with type 1 diabetes.



Interventions to encourage active lifestyles are imperative for adolescents with diabetes.

title: Cardiovascular Endurance and Heart Rate Variability in Adolescents With Type 1 or Type 2 Diabetes
abstract: Incidence rates of both type 1 and type 2 diabetes mellitus (DM) are increasing in youth and may eventually contribute to premature heart disease in early adulthood. This investigation explored the influence of type of diabetes, gender, body mass index (BMI), metabolic control (HbA 1c ), exercise beliefs and physical activity on cardiovascular endurance (CE), and heart rate variability (HRV). Differences in exercise beliefs, physical activity, HRV, and CE in youth with type 1 versus type 2 DM were determined.  Adolescents with type 1 DM (n = 105) or with type 2DM (n = 27) completed the Exercise Belief Instrument and the Physical Activity Recall. Twenty-four HRV measures were obtained via Holter monitoring and analyzed using SpaceLabs Vision Premier™ software system. The McMaster cycle test was used to measure CE (V0 2peak).  Regardless of the type of DM, females and those with higher BMI, poorer metabolic control, and lower amounts of physical activity tended to have lower levels of CE. Exercise beliefs consistently predicted both frequency and time domain HRV measures. Measures of exercise beliefs, self-reported physical activity, CE (V0 2peak), and HRV were significantly lower in adolescents with type 2 DM in comparison to those with type 1 DM.  Early findings of poor physical fitness, lower HRV, fewer positive beliefs about exercise, and less active lifestyles highlight the importance of developing culturally sensitive interventions for assisting youth to make lifelong changes in their physical activity routines. Females, those with poorer metabolic control, and minority youth with type 2 DM may be particularly vulnerable to later cardiovascular disease.

title: Type 2 diabetes in youth: a phenotype of poor cardiorespiratory fitness and low physical activity.
abstract: The increased incidence of obesity and type 2 diabetes (T2D) among youth has prompted the development of guidelines for healthy cardiorespiratory fitness (CRF) and physical activity (PA) levels in the pediatric population. It is unclear whether youth with T2D meet these guidelines as previous research has not included type 2 diabetics. Therefore, the purpose of this investigation was to examine CRF and PA in youth with T2D and compare these results with recently published normative data for CRF and guidelines for PA in youth.  Forty adolescents (17 males and 23 females) with T2D were assessed for moderate-to-vigorous PA via the 7-day PA recall. CRF was determined by a progressive cycle ergometer test and indirect calorimetry. PA levels were compared with recently published guidelines for youth of 60 minutes per day, and CRF data were compared with age- and sex-adjusted normative values from the National Health and Nutrition Examination Survey 1999-2002.  Only 17.6% (3/17) of boys and 21.7% (5/23) of girls met PA guidelines, while none of the participants met criteria for healthy CRF. When compared with normative CRF data for US youth, approximately 93% of boys and 95% of girls scored below the 10th percentile.



These results suggest that youth with T2D exhibit low levels of CRF and the majority do not participate in recommended amounts of PA. Practitioners working with type 2 diabetic youth need to emphasize the importance of regular PA to increase CRF and promote cardiovascular health in an effort to decrease long-term diabetes-related complications.

title: Impact of physical activity on heart rate variability in children with type 1 diabetes
abstract: ObjectiveChildren with type 1 diabetes are usually associated with cardiovascular autonomic neuropathy. The present study explored the influence of physical activity on their autonomic nervous function by measuring the heart rate variability (HRV).Materials and methodsA total of 93 type 1 diabetic children and 107 healthy control subjects were enrolled. The Physical Activity Questionnaire for Children (PAQ-C) was adopted to determine the physical activity level as low, moderate, or high activity. HRV was determined by frequency analysis and measured in both resting and active states.ResultsChildren with type 1 diabetes had significantly lower HRV than that of healthy control subjects in resting state but not in active state. The decreased HRV in diabetic children was observed only in subjects with low physical activity. The HRV in diabetic children with moderate to high physical activity, however, was not different from that of their healthy controls.ConclusionsDiabetic children should be encouraged to engage in physical activity with more intensity, which can benefit their autonomic nervous function. Nevertheless, the potential risk of vigorous activity still needs our concern.

title: Impaired Energy Expenditure Despite Normal Cardiovascular Capacity in Children with Type 1 Diabetes
abstract: Benefit of fitness on children with type 1 diabetes mellitus (T1DM) is still debated.  To evaluate the influence of physical activity on metabolic balance and exercise tolerance in prepubertal children affected by T1DM.  We analyzed 35 pre-/peripubertal T1DM children and 31 matched controls using an activity monitor (SenseWear Armbad) and physical activity questionnaire (PAQ) to assess energy expenditure (EE), total and active, sedentary and physical activities (h/day and Mets = metabolic equivalents). The maximal cardiopulmonary exercise test (CPET) was also performed.  Total physical activities and total and active EE (>3 Mets) resulted higher in controls than in T1DM patients and self-reported perception of physical and sedentary activities was altered in T1DM children as well in controls and were different from the measured data. No differences were found in CPET parameters with the exception of a higher maximal blood pressure in T1DM children. In multivariate analysis HbA1c negatively correlated with VO2.  Prepubertal T1DM children seem to have a lower level of physical activity and EE and a probable altered feeling of physical and sedentary activities. On the other hand, T1DM children do not show any alteration of cardiovascular performance, although glycemic control (HbA1c) may play a role in cardiovascular performance.

title: Adherence to physical activity in young people with type 1 diabetes.
abstract: Regular physical activity plays a key role in the management of children and adolescents with Type 1 diabetes mellitus but it is not considered as a treatment for diabetes. Aim of this study was to investigate time spent exercising, adherence to the programme for a safe exercise and ability of young people with diabetes to take appropriate measures to reduce potential risks. Ninety one Type 1 diabetes mellitus young people (aged from 10 to 18 years, duration of diabetes longer than 6 months) without associated chronic diseases were randomly enrolled in the study. Age, sex, weight, height, BMI, duration of disease, mean HbA1c value over preceding 6 months have been collected. The time weekly spent for physical activity, the type of exercise usually performed, the measures taken to reduce exercise risks have been collected by a structured questionnaire. BMI was 21.6+/-3.05 in the boys and 21.3+/-3.63 in the girls. All patients spent exercising 438+/-221 minutes/week. Boys exercised 71 minutes longer than girls in competitive sports. Children exercising less than 60 minutes weekly showed a mean HbA1c level (8,9+/-05%) higher than that found in children exercising 120-360 minutes (8,3+/-0.4 %; p=0.002) or 360-480 minutes (8,0+/-0.6 %; p< 0.01) weekly. Children attending a competitive sport (at least 360 min per week) had a better glycemic control (HbA1c=7,39+/-0.6 %; p=0.03) than other active peers. Fifty percent of patients reported to monitor blood glucose levels during exercise; 32 % changed insulin dose according to blood glucose levels; 60 % usually added carbohydrate-based foods before (35%), during (15%) or after (10%) exercise. Hypoglycemic episodes (37.7%) were reported more frequently than hyperglycemic ones (p=0.024), but only twelve percent of them were symptomatic and appeared 30 minutes to 2 hours after the end of exercise. These results must encourage health care professionals to review regularly the ability of their patients in managing physical activity and to check their adherence to the program for a safe exercise.

title: Physical Activity and Glycaemic Control in Children with Diabetes Mellitus
abstract: The relationship between physical activity, glycaemic control, and skinfold thickness was studied in children with diabetes. Patients recorded details of activity in a home diary over a 6‐day period, and provided eight serial capillary dried blood spots for glucose analysis during a 24‐h period. Levels of activity were assessed using a semi‐quantitative scoring scheme. No correlation was found between total activity score and glycaemic control. However, the activity score before 9 am showed significant correlation with mean blood glucose (p = 0.005) and fructosamine (p = 0.04). The time of rising in the morning showed significant correlation with blood glucose after lunch (p = 0.004) and with fructosamine (p = 0.04). A significant correlation was found between early morning activity and subscapular skinfold thickness. The association between activity and glycaemic control warrants further investigation, as it suggests that patients who engage in energetic activity early in the morning may achieve lower blood glucose and fructosamine levels than their less active peers.

title: Physical activity and diabetes.
abstract: Although physical activity is frequently recommended in the management of type Idiabetes it has not yet been established whether practising regular exercise could actually improve the long-term outcome of metabolic control. In this follow-up study we assessed the impact of long-term physical activity in patients with type 1 diabetes mellitus. We studied longitudinally 69 patients with type 1 diabetes mellitus, 43 boys and 26 girls aged at onset of the disease 8.98 +/- 3.90 years with a mean duration of the disease of 97 +/- 63 months. The patients were classified according to the duration of the disease in 3 groups [A:24-60 months (69); B: 61-120 months (41); C > or =121 months (19)]. The average time spent weekly doing exercise was recorded for each patient in the three duration periods taken into account. On average our patients reported 3.0 +/- 2.9 hours of physical activity per week. On the basis of the hour/week of physical activity we divided the patients into 4 groups [G1: <2 hrs/week (46%); G2: 2-4 hrs/week (29%); G3 >4 hrs/week (22%) > or =7 hrs/week (3%)]. The duration group B showed a significant lower HbAlc and HbA1c adjusted for duration of the disease in G4 compared to G2 (p < 0.05) and G3 (p < 0.05). No differences were found for insulin requirement, weight excess, blood pressure and heart rate between active and sedentary patients. According to our results we concluded that exercise can improve the quality of metabolic control only if it is adjusted to the training level of the patient.

title: Levels and patterns of physical activity in children and adolescents with type 1 diabetes and associated metabolic and physiologic health outcomes.
abstract: The current study objectively assessed physical activity (PA) levels and patterns in children and adolescents with type 1 diabetes and compared the metabolic and physiologic health profiles of those achieving and those not achieving the current recommendation of 60 minutes a day (minutes x D(-1)) of at least moderate intensity PA.



37 children and adolescents (20 boys, 17 girls) aged 12.7 +/- 2.1 years (mean +/- SD), disease duration 5.9 +/- 3.0 years participated. PA was assessed using heart rate monitoring. Peak VO(2), BMI, sum of 5 skinfolds, HbA(1c), and daily insulin dosage were also determined.



Mean accumulated time in moderate-to-vigorous intensity PA was 53.6 +/- 31.4 minutes x D(-1). Levels of vigorous-intensity PA were low, mean 8.3 +/- 10.2 minutes x D(-1). When controlling for age, no differences in metabolic or physiologic health outcomes were evident between those individuals achieving, and those not achieving, 60 minutes x D(-1) of moderate-to-vigorous intensity PA. PA predominantly occurred in short bouts lasting 5 minutes or less.



The efficacy of accumulating 60 minutes x D(-1) of moderate-to-vigorous intensity PA, in the form of short duration, intermittent bouts of largely unplanned PA, to promote health gains in children and adolescents with type 1 diabetes is questionable.

title: Physical activity and psychological well-being in children with Type 1 diabetes
abstract: Physical activity and psychological well-being contribute to positive lifestyle and well-being in youngsters who have Type 1 diabetes. The aims of this study were to objectively assess the physical activity levels of children with Type 1 diabetes, and investigate associations between physical activity levels, psychological well-being and HbA1c. Thirty-six children, mean age 12.8 years, participated in the investigation. Physical activity was assessed using heart rate monitoring over four days. Children further completed the Diabetes Quality of Life for Youths Questionnaire, the Physical Self-Perception Profile for Children and the Self-Efficacy for Diabetes Scale. Routine outpatient HbA1c measurements were recorded. There were no significant associations between psychological well-being and physical activity, or HbA1c and physical activity, thus suggesting physical activity does not directly relate to psychological well-being in children with Type 1 diabetes. It may be that the effect of physical activity differs from that in children without Type 1 diabetes because of the place of physical activity within diabetes management and the need to balance this with insulin dosage and dietary intake to maintain blood glucose levels.

title: Patterns of physical activity determined by heart rate monitoring among diabetic children
abstract: Children with type 1 diabetes should be encouraged to participate in physical activity because exercise can benefit insulin sensitivity and improve known risk factors for atherosclerosis.  Physical activity patterns of 127 children and adolescents with stable type 1 diabetes were investigated by 24 hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of physical activity at different intensities. The results were compared with normative data.  Diabetic preschoolchildren accumulated 192.7 (78.1), 39.1 (24.3), and 21.3 (9.4) minutes/day (mean (SD)) of light, moderate, and vigorous physical activity, respectively. At the same activity levels, diabetic schoolchildren accumulated 168.9 (76.7), 37.9 (15.9), and 19.0 (14.8) minutes/day, and diabetic teenagers accumulated 166.3 (67.5), 45.6 (26.9), and 25.2 (15.3) minutes/day. Diabetic schoolchildren were significantly more active than healthy peers when considering moderate activity; diabetic teenagers were significantly more active when considering moderate and vigorous activity. There was a negative correlation between the most recent glycated haemoglobin and the time spent in light activities in schoolchildren, and a negative correlation between mean glycated haemoglobin for one year and time spent in light and moderate activities in schoolchildren.  The majority of our diabetic patients meet the classical paediatric guidelines for physical activity and compare favourably with their healthy peers.

title: Skin microvascular reactivity in children and adolescents with type 1 diabetes in relation to levels of physical activity and aerobic fitness.
abstract: No studies to date have evaluated the relationship between exercise and microvascular function in youth with type 1 diabetes mellitus (T1DM). Twenty-nine complication free children and adolescents with T1DM were assessed for skin microvascular reactivity, aerobic fitness (VO2peak) and physical activity. VO2peak but not physical activity was significantly and independently associated with maximal hyperemia of the skin microcirculation (p < .01). No significant associations were found between venoarteriolar reflex (VAR) vasoconstriction and VO2peak or physical activity. Aerobic fitness may be an important indicator or mediator of effective microvascular endothelial function in youth with T1DM.

title: Impact of Physical Fitness and Glycemic Control on In Vivo Insulin Action in Adolescents With IDDM
abstract: The relationship of in vivo insulin-mediated glucose utilization to the state of physical fitness and the degree of glycemic control was examined in 27 adolescents with insulin-dependent diabetes mellitus (IDDM) compared with 10 nondiabetic adolescent control subjects. In vivo total-body insulin-mediated glucose metabolism was evaluated by the hyperinsulinemic-euglycemic clamp. Physical fitness was assessed by maximal oxygen consumption (Vo2 max) during cycle ergometry. Patients and control subjects had similar levels of Vo2 max (34.9 ± 8.6 vs. 38.6 ± 9.9 ml · kg−1 · min−1, P = 0.3). Patients had lower total-body insulin-mediated glucose metabolism compared with control subjects (33.9 ± 14.3 vs. 63.8 ± 17.2 μmol · kg−1 · min−1, P = 0.0002). Among the patients, females had lower total-body insulin-mediated glucose metabolism compared with males (24.2 ± 2.8 vs. 40.7 ± 3.4 μmol · kg−1 · min−1, P < 0.001); however, this difference disappeared after correcting for sex differences in fitness levels. Insulin-mediated glucose metabolism correlated with Vo2 max in patients and control subjects (r = 0.83, r = 0.81, P < 0.05). The regression of total-body insulin-mediated glucose metabolism on Vo2 max for patients was −2.84 ± 0.255 Vo2 max and for control subjects was 7.12 ± 0.143 Vo2 max, indicating that for similar degrees of physical fitness patients have lower total body insulin-mediated glucose metabolism levels than control subjects. In patients, total-body insulin-mediated glucose metabolism correlated with the degree of glycemic control as assessed by the level of glycosylated hemoglobin (r = −0.63, P < 0.001). In a multiple regression analysis including Vo2 max and glycosylated hemoglobin, the coefficient of determination explaining the variation in total-body insulin-mediated glucose metabolism was 73%. It is concluded that adolescents with IDDM are insulin resistant compared with healthy control subjects, and this resistance is attributable to the state of diabetes control. However, the level of physical fitness explains a major part of interindividual variation in insulin action in both control subjects and adolescents with IDDM.

title: The Relationship of Physical Fitness to Lipid and Lipoprotein(a) Levels in Adolescents With IDDm
abstract: Increased physical activity and physical fitness are recommended therapeutic modalities in addition to insulin and diet in the management of children with IDDM. The aim of this study was to assess the fitness levels of adolescents with IDDM compared with healthy control subjects and to evaluate the relationship between physical fitness and metabolic control.  We studied 59 patients with IDDM, 28 boys and 31 girls, age 15.6 ± 2.5 yr, duration of diabetes 7.6 ± 3.5 yr, HbA1 10.6 ± 2.1% (mean ± SD), and compared them with 18 healthy, nondiabetic control subjects, 9 boys and 9 girls, matched for age, BMI, and Tanner stage. Physical fitness was measured by VO2max during progressive bicycle ergometry. HbA1 was used to determine glycemic control. Lipid profile included fasting total cholesterol, HDL, LDL, Lp(a), and TG levels.  Patients with IDDM had lower VO2max levels than control subjects (33.7 ± 7.0 vs. 41.0 ± 10.4 ml · kg−1 · min−1, P = 0.001). Males with IDDM had lower VO2max than male control subjects, but diabetic and control females showed no difference. In IDDM patients, VO2max correlated inversely with HbA1, insulin dose, cholesterol, LDL, TGs, and Lp(a), but did not correlate with HDL, which correlated inversely with BMI.  We conclude that the state of physical fitness is an important correlate of lipid levels and Lp(a) in adolescents with IDDM. We speculate that higher physical fitness levels in adolescents with IDDM may decrease the risk of CVD through modulating lipid levels.

title: Physical fitness of children and adolescents with insulin-dependent diabetes mellitus.
abstract: The physical working capacity (PWC170) of 84 children and adolescents with insulin-dependent diabetes mellitus (IDDM) and of 94 non-diabetic subjects was measured by a submaximal progressive exercise test. The age of the diabetic subjects ranged from 6.3 to 18.8 years and that of the control subjects from 8.5 to 18.8 years. The PWC170 of diabetic boys was lower than that of non-diabetic boys (p less than 0.01) while no difference was observed between diabetic and non-diabetic girls. PWC170 was inversely related to age (p less than 0.01) and concentration of hemoglobin A1 (p less than 0.025) in diabetic boys but not in diabetic girls. No relationship was observed between PWC170 and duration of diabetes in either boys or in girls. The results indicate that good physical fitness in boys is associated with a better metabolic control. Hence the study indirectly supports previous observations that physical activity improves the metabolic control of IDDM.

title: Lower cardiorespiratory fitness in children with Type 1 diabetes
abstract: (2011)

title: Physical activity and energy intake in adolescent girls with Type 1 diabetes
abstract: Girls with Type 1 diabetes often gain excessive weight during puberty. The aims of this study were to compare objectively assessed physical activity and energy intake in girls with Type 1 diabetes with those in healthy age‐matched controls.

title: Preclinical noninvasive markers of atherosclerosis in children and adolescents with type 1 diabetes are influenced by physical activity.
abstract: To measure preclinical noninvasive markers of atherosclerosis in youth with type 1 diabetes (T1DM), and to determine their associations between physical activity level and cardiorespiratory fitness (maximal oxygen consumption [VO2max]).



This was a cross-sectional study including 32 patients with T1DM and 42 healthy subjects aged 6 to 17 years. Main outcome measures included arterial flow-mediated dilation (FMD) and intima-media thickness with high-resolution ultrasonography; physical activity by accelerometer (valid 26 patients with T1DM, 35 healthy subjects) and VO2max.



Compared with healthy control subjects, patients with T1DM had higher intima-media thickness (mean 0.50 mm [0.48-0.52, 95% CI] vs 0.48 [0.47-0.49], P=.02) and reduced FMD (4.9% [4.1%-5.7%] vs 7.3 [6.4-8.1], P=.001), VO2max (45.5 mL/kg/min [43.0-48.0] vs 48.7 [46.7-50.6], P<or=.001), total (567.1 [458.6-675.6] vs 694.9 [606.6-883.2] counts per minute, P=.001) and moderate-to-vigorous physical activity. Patients with T1DM who did more than 60 min/day(-1) of moderate-to-vigorous physical activity had similar FMD compared with relatively inactive healthy subjects, but not as high as active control subjects.



Youth with T1DM present early signs of atherosclerosis, as well as low physical activity level and cardiorespiratory fitness. Endothelial function is enhanced in patients who practice more than 60 min/day(-1) of moderate-to-vigorous physical activity.

title: A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review
abstract: BackgroundAccurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary) and objectively (directly measured; e.g. accelerometry, doubly labeled water) assessed physical activity in adults.MethodsEight electronic databases were searched to identify observational and experimental studies of adult populations. Searching identified 4,463 potential articles. Initial screening found that 293 examined the relationship between self-reported and directly measured physical activity and met the eligibility criteria. Data abstraction was completed for 187 articles, which described comparable data and/or comparisons, while 76 articles lacked comparable data or comparisons, and a further 30 did not meet the review's eligibility requirements. A risk of bias assessment was conducted for all articles from which data was abstracted.ResultsCorrelations between self-report and direct measures were generally low-to-moderate and ranged from -0.71 to 0.96. No clear pattern emerged for the mean differences between self-report and direct measures of physical activity. Trends differed by measure of physical activity employed, level of physical activity measured, and the gender of participants. Results of the risk of bias assessment indicated that 38% of the studies had lower quality scores.ConclusionThe findings suggest that the measurement method may have a significant impact on the observed levels of physical activity. Self-report measures of physical activity were both higher and lower than directly measured levels of physical activity, which poses a problem for both reliance on self-report measures and for attempts to correct for self-report – direct measure differences. This review reveals the need for valid, accurate and reliable measures of physical activity in evaluating current and changing physical activity levels, physical activity interventions, and the relationships between physical activity and health outcomes.

title: Computer use, free time activities and metabolic control in patients with type 1 diabetes.
abstract: We investigated the influence of computer's use on metabolic control in 115 patients with type 1 diabetes (DM1). Multiple linear regression showed that HbA1c% was not related to age, DM1 duration, TV watching or computer use but was independently and negatively related to the weekly hours spent on physical exercise.

title: How many steps/day are enough? for children and adolescents
abstract: Worldwide, public health physical activity guidelines include special emphasis on populations of children (typically 6-11 years) and adolescents (typically 12-19 years). Existing guidelines are commonly expressed in terms of frequency, time, and intensity of behaviour. However, the simple step output from both accelerometers and pedometers is gaining increased credibility in research and practice as a reasonable approximation of daily ambulatory physical activity volume. Therefore, the purpose of this article is to review existing child and adolescent objectively monitored step-defined physical activity literature to provide researchers, practitioners, and lay people who use accelerometers and pedometers with evidence-based translations of these public health guidelines in terms of steps/day. In terms of normative data (i.e., expected values), the updated international literature indicates that we can expect 1) among children, boys to average 12,000 to 16,000 steps/day and girls to average 10,000 to 13,000 steps/day; and, 2) adolescents to steadily decrease steps/day until approximately 8,000-9,000 steps/day are observed in 18-year olds. Controlled studies of cadence show that continuous MVPA walking produces 3,300-3,500 steps in 30 minutes or 6,600-7,000 steps in 60 minutes in 10-15 year olds. Limited evidence suggests that a total daily physical activity volume of 10,000-14,000 steps/day is associated with 60-100 minutes of MVPA in preschool children (approximately 4-6 years of age). Across studies, 60 minutes of MVPA in primary/elementary school children appears to be achieved, on average, within a total volume of 13,000 to 15,000 steps/day in boys and 11,000 to 12,000 steps/day in girls. For adolescents (both boys and girls), 10,000 to 11,700 may be associated with 60 minutes of MVPA. Translations of time- and intensity-based guidelines may be higher than existing normative data (e.g., in adolescents) and therefore will be more difficult to achieve (but not impossible nor contraindicated). Recommendations are preliminary and further research is needed to confirm and extend values for measured cadences, associated speeds, and MET values in young people; continue to accumulate normative data (expected values) for both steps/day and MVPA across ages and populations; and, conduct longitudinal and intervention studies in children and adolescents required to inform the shape of step-defined physical activity dose-response curves associated with various health parameters.

title: Accelerometer assessment of physical activity in children: an update.
abstract: Accelerometry is frequently used to assess physical activity in children. The number of articles in this area has increased dramatically in the last 10 years. The aim of this article is to provide a contemporary overview of accelerometry research in children. Specifically, the review addresses the choice of monitor, choice of epoch, when and for how long activity should be measured, the lack of consensus over how to define a complete day of activity data, issues of compliance, methods for the calibration of activity output, and the richness of data available from accelerometry.

title: Energy cost of physical activities in children: validation of SenseWear Armband.
abstract: To examine the validity of SenseWear Pro2 Armband in assessing energy cost of physical activities in children, and to contribute with values of energy costs in an overview of physical activities in children.



Energy cost was assessed by SenseWear Pro2 Armband in 20 healthy children, 11-13 yr, while lying down resting, sitting playing games on mobile phone, stepping up and down on a step board, bicycling on a stationary bike, jumping on a trampoline, playing basketball, and walking/running on a treadmill at the speeds 2, 3, 4, 5, 6, 7, 8, and 10 km x h(-1). During these activities, energy cost was also assessed from VO2 and VCO2 measured by Oxycon Mobile portable metabolic system, which was used as criterion method.



The difference in energy cost between SenseWear Pro2 Armband and Oxycon Mobile was -0.7 (0.5) (P < 0.001) for resting, -2.0 (0.9) (P < 0.001) for playing games on mobile phone, -6.6 (2.3) (P < 0.001) for stepping on the step board, -12.0 (3.7) (P < 0.001) for bicycling, -2.7 (11.9) (P = 0.34) for jumping on the trampoline, and -14.8 (6.4) kJ x min(-1) (P < 0.001) for playing basketball. The difference in energy cost between SenseWear Pro2 Armband and Oxycon Mobile for increasing treadmill speed was 1.3 (3.1) (P = 0.048), 0.1 (2.9) (P = 0.82), -1.2 (2.6) (P = 0.049), -1.6 (3.2) (P = 0.044), -3.1 (3.7) (P = 0.0013), -4.9 (3.7) (P < 0.001), -5.3 (3.7) (P < 0.001), and -11.1 (3.5) kJ x min(-1) (P < 0.001).



SenseWear Pro2 Armband underestimated energy cost of most activities in this study, an underestimation that increased with increased physical activity intensity. A table of energy costs (MET values) of physical activities in children measured by indirect calorimetry is presented as an initiation of the creation of a compendium of physical activities in children.

title: Evaluation of a portable device to measure daily energy expenditure in free-living adults.
abstract: Increasing daily energy expenditure (EE) plays an important role in the prevention or treatment of several lifestyle-related diseases; however, its measurement remains problematic.



The objective was to evaluate a portable armband device for measuring daily and physical activity EE compared with doubly labeled water (DLW) in free-living individuals.



Daily EE and physical activity EE were measured in 45 subjects over a 10-d period simultaneously with 2 techniques: a portable armband and DLW. Resting metabolic rate was measured by indirect calorimetry, and the thermic effect of a meal was estimated (10% of daily EE). Physical activity EE was obtained by subtracting the values for resting metabolic rate and thermic effect of a meal measured with DLW from those measured with the armband. Body composition was measured with dual-energy X-ray absorptiometry. Concordance between measures was evaluated by intraclass correlation, SEE, regression analysis, and Bland-Altman plots.



Mean estimated daily EE measured with the armband was 117 kcal/d lower (2375 +/- 366 kcal/d) than that measured with DLW (2492 +/- 444 kcal/d; P < 0.01). Despite this group difference, individual comparisons between the armband and DLW were close, as evidenced by an intraclass correlation of 0.81 (P < 0.01).



The portable armband shows reasonable concordance with DLW for measuring daily EE in free-living adults. The armband may therefore be useful to estimate daily EE.

title: Insulin resistance in adolescents with type 2 diabetes is associated with impaired exercise capacity.
abstract: The incidence of pediatric type 2 diabetes (T2D) is rising, with unclear effects on the cardiovascular system. Cardiopulmonary fitness, a marker of morbidity and mortality, is abnormal in adults with T2D, yet the mechanisms are incompletely understood.



We hypothesized that cardiopulmonary fitness would be reduced in youth with T2D in association with insulin resistance (IR) and cardiovascular dysfunction.



We conducted a cross-sectional study at an academic hospital that included 14 adolescents (age range, 12-19 yr) with T2D, 13 equally obese adolescents and 12 lean adolescents similar in age, pubertal stage, and activity level.



Cardiopulmonary fitness was measured by peak oxygen consumption (VO(2)peak) and oxygen uptake kinetics (VO(2)kinetics), IR by hyperinsulinemic clamp, cardiac function by echocardiography, vascular function by venous occlusion plethysmography, body composition by dual-energy x-ray absorptiometry, intramyocellular lipid by magnetic resonance spectroscopy, and inflammation by serum markers.



Adolescents with T2D had significantly decreased VO(2)peak and insulin sensitivity, and increased soleus intramyocellular lipid, C-reactive protein, and IL-6 compared to obese or lean adolescents. Adolescents with T2D also had significantly prolonged VO(2)kinetics, decreased work rate, vascular reactivity, and adiponectin, and increased left ventricular mass and fatty acids compared to lean adolescents. In multivariate linear regression analysis, IR primarily, and fasting free fatty acids and forearm blood flow secondarily, were significant independent predictors of VO(2)peak.



Given the strong relationship between decreased cardiopulmonary fitness and increased mortality, these findings in children are especially concerning and represent early signs of impaired cardiac function.

title: Physical Activity in Youth With Well-Controlled Versus Poorly Controlled Type 2 Diabetes
abstract: Type 2 diabetes increases risk of chronic disease. The recommendations are for youth to attain at least 60 minutes of daily physical activity (PA). Fewer than 20% achieve this goal. This study examines differences between blood glucose control and PA in youth with type 2 diabetes.  A1c levels and PA were tested in youth 9 to 17 years old with newly diagnosed type 2 diabetes during clinic visits. Average daily minutes of moderate to vigorous physical activity (MVPA) was calculated. Differences in MVPA were investigated.  Slightly more than half of youth had well-controlled diabetes. All engaged in less PA than recommended. Youth with well-controlled diabetes engaged in slightly less MVPA than those whose diabetes was not in control. There were no significant differences in minutes of MVPA by gender, race, or diabetes control.  It is necessary to identify ways to increase PA among youth with type 2 diabetes.

title: Sedentary behaviour in youth
abstract: The purpose of this review is to describe the amount of time children spend in sedentary behaviour and to determine if there are specific factors that associate with sedentary behaviour in children. The following search terms were used to identify relevant articles: sedentary behaviour, inactivity, television, computer, video games, small screen, sitting, prevalence, patterns, correlates, factors and determinants. The databases used to conduct the search included PubMed, PsycINFO, ERIC (Education Resources Information Center) and Academic Search Premier. The studies reviewed were limited to those that sampled children (2–18 years), were written in English and used a measure of sedentary behaviour as the dependent variable. Several studies reported the time spent watching television or the proportion of children at or above a threshold for television viewing (eg, ≥3 h/day). Among the accelerometer studies included, the National Health and Nutrition Examination Survey is the largest and reported ∼6.1, 7.5 and 8.0 h/day mean sedentary time in children 6–11, 12–15 and 16–19 years old, respectively. Taken together, the existing literature across the world indicates a slightly higher level of sedentary behaviour in older children. Higher levels of sedentary behaviour were also reported in non-white children, children from lower socioeconomic status background and children from households with more access to televisions/computers. Lower levels of sedentary behaviour were reported in children whose parents have rules/limitations on screen time.

title: Prediction of physical activity and physical work capacity (PWC150) in young adulthood from childhood and adolescence with consideration of parental measures
abstract: The 12‐year prediction of physical activity level and submaximal aerobic fitness observed during young adulthood was quantified from childhood and parental measures. The sample consisted of 153 children and adolescents of the Québec Family Study who were evaluated at baseline and reassessed 12 years later, as young adults. Physical work capacity at a heart rate of 150 beats · min−1 (PWC150) was measured using cycle ergometry. A 3‐day activity record was used to estimate daily energy expenditure (DEE), inactive time (IA), and time spent in moderate‐to‐vigorous activity (MVPA). Spearman partial inter‐age correlations, controlling for length of follow‐up and age at baseline, indicated better tracking for PWC150 (0.24 and 0.46, males and females, respectively) than for indicators of physical activity (0.07 ≤ r ≤ 0.25, males; 0.06 ≤ r ≤ 0.22, females). Multiple regression analyses indicated that parental measurements of activity and PWC150 did not add any predictive value, with the exception of paternal DEE, which accounted for 8% of the variance in males. There is moderately high stability of submaximal work capacity and lower tracking of physical activity from childhood and adolescence into young adulthood.  2001.

title: Impaired stroke volume and aerobic capacity in female adolescents with type 1 and type 2 diabetes mellitus
abstract: hypothesisThis study was designed to determine whether type 2 diabetic adolescents have reduced aerobic capacity and to investigate the role of cardiac output and arteriovenous oxygen difference (a−vO2) in their exercise response.MethodsFemale adolescents (age 12–18 years) with type 2 diabetes mellitus (n = 8) and type 1 diabetes mellitus (n = 12) and obese (n = 10) and non-obese (n = 10) non-diabetic controls were recruited for this study. Baseline data included maximal aerobic capacity (cycle ergometer) and body composition. Cardiac output and a−vO2 were determined at rest and during submaximal exercise.ResultsDiabetic groups had lower aerobic capacity than non-diabetic groups (p < 0.05). Adolescents with type 2 diabetes had lower aerobic capacity than the type 1 diabetic group. Maximal heart rate was lower in the type 2 diabetic group (p < 0.05). Exercise stroke volume was 30–40% lower at 100 and 120 beats per min in the diabetic than in the non-diabetic groups (p < 0.05). The a−vO2 value was not different in any condition.Conclusions and interpretationType 2 diabetic adolescents have reduced aerobic capacity and reduced heart rate response to maximal exercise. Furthermore, type 2 and type 1 diabetic adolescent girls have a blunted exercise stroke volume response compared with non-diabetic controls. Central rather than peripheral mechanisms contribute to the reduced aerobic capacity in diabetic adolescents. Although of short duration, type 2 diabetes in adolescence is already affecting cardiovascular function in adolescents.

title: Hepatic Steatosis and Low Cardiorespiratory Fitness in Youth With Type 2 Diabetes
abstract: The purpose of this study was to examine the association between cardiorespiratory fitness, ectopic triglyceride accumulation, and insulin sensitivity among youth with and without type 2 diabetes. Subjects included 137 youth ages 13–18 years including 27 with type 2 diabetes, 97 overweight normoglycemic controls, and 13 healthy weight normoglycemic controls. The primary outcome measure was cardiorespiratory fitness defined as peak oxygen uptake indexed to fat free mass. Secondary outcomes included liver and muscle triglyceride content determined by 1H‐magnetic resonance spectroscopy and insulin sensitivity determined by frequently sampled intravenous glucose tolerance test. Despite similar measures of adiposity, peak oxygen uptake was 11% lower (38.9 ± 7.9 vs. 43.9 ± 6.1 ml/kgFFM/min, P = 0.002) and hepatic triglyceride content was nearly threefold higher (14.4 vs. 5.7%, P = 0.001) in youth with type 2 diabetes relative to overweight controls. In all 137 youth, cardiorespiratory fitness was negatively associated with hepatic triglyceride content (r = −0.22, P = 0.02) and positively associated with insulin sensitivity (r = 0.29, P = 0.002) independent of total body and visceral fat mass. Hepatic triglyceride content was also negatively associated with insulin sensitivity (r = −0.35, P < 0.001), independent of adiposity, sex, age, and peak oxygen uptake. This study demonstrated that low cardiorespiratory fitness and elevated hepatic triglyceride content are features of type 2 diabetes in youth. Furthermore, cardiorespiratory fitness and hepatic triglyceride are associated with insulin sensitivity in youth. Taken together, these data suggest that cardiorespiratory fitness and hepatic steatosis are potential clinical biomarkers for type 2 diabetes among youth.

title: Cardiorespiratory fitness levels among US youth 12 to 19 years of age: findings from the 1999-2002 National Health and Nutrition Examination Survey.
abstract: To assess cardiorespiratory fitness levels in youth aged 12 to 19 years and to examine associations between fitness and age, sex, race/ethnicity, and self-reported physical activity in this age group.



Cross-sectional study.



The National Health and Nutrition Examination Survey's mobile examination center, throughout the United States from 1999-2002.



A representative sample of 4732 youth aged 12 to 19 years was examined; 3287 completed the treadmill test and were included in the analysis. The National Center for Health Statistics conducted the survey.  Age, sex, race/ethnicity, weight status, self-reported physical activity, and television viewing.  Estimated maximal oxygen uptake (VO2max) determined by a submaximal treadmill exercise test.



Estimated VO2max (mL.kg(-1) . min(-1)) was higher in males (mean +/- SE, 46.4 +/- 0.4) than in females (mean +/- SE, 38.7 +/- 0.3) but did not differ across race/ethnicity groups. Among males, older participants had higher VO2max values, while in females, younger participants had higher values. For both males and females, those in the normal weight group had higher fitness levels than those in the at risk for overweight and overweight groups. Approximately one third of both males and females failed to meet recommended standards for cardiorespiratory fitness.



In US youth, cardiorespiratory fitness is lower in males and females who are overweight than in those of normal weight, but fitness is not related to race/ethnicity. Youth who have low levels of physical activity and high levels of sedentary behavior are also more likely to have lower cardiorespiratory fitness.

title: Tracking of Physical Fitness From Childhood to Adulthood
abstract: Resume The purpose of the present study was to investigate the tracking of selected aspects of physi- cal fitness (peak handgrip force, sit-ups, aerobic fitness, and blood pressure) from child- hood to adulthood. The investigation studied a randomly selected subgroup from the origi- nal participants in the Trois-Rivieres growth and development study, 95 women (57 experi- mental and 38 control) and 96 men (56 experimental and 40 control). During their pri- mary-school education, the experimental group had received 5 hours of physical education each week whereas the control group had received 40 minutes per week. Data were gath- ered when subjects were 10-12 years old (baseline) and during follow-up around the age of 35 years. Tracking between 10, 11, 12, and 35 years of age was assessed by correlation analysis. In females the tracking of grip strength increased from the interval 10-35 to the intervals 11-35 and 12-35 years of age (r = 0.54 to 0.69 and 0.67, respectively, all p < 0.001). In males the tracking of grip strength was less consistent, but also increased over the same intervals to become significant for the correlation between 12 and 35 years of age (r = 0.32, p < 0.05). Tracking for sit-ups also increased, from 0.29 to 0.38 for females and from 0.23 to 0.54 for males. The tracking of PWC 170/kg between 11 and 35 years was sig-

title: Normal physical working capacity in prepubertal children with type 1 diabetes compared with healthy controls
abstract: Exercise testing has become a valuable help for the physician to examine the influence of recommended exercise training on physical fitness. However, the question as to how diabetic prepubertal children differ from their non‐diabetic peers in their performance capacity has only partial and sometimes conflicting answers in the literature.  The aim of the current study was thus to evaluate aerobic fitness during an incremental submaximal test (measure of the Physical Working Capacity 170 (PWC170)) in 17 well‐controlled prepubertal insulin‐dependent diabetic boys aged 8.5–13 y. Eighteen healthy prepubertal boys matched for age, body size and physical activity served as controls. Part of the method was to check capillary blood glucose level in the diabetic patients and in nine of the healthy subjects throughout the exercise.  From this experiment it appeared that the level of physical fitness was similar in diabetic and healthy boys (PWC170 2.28±0.09 vs 2.37±0.13 W·kg−1). While glucose homeostasis was well maintained in the healthy group, diabetic children showed a marked fall in blood glucose during the exercise. In addition, the PWC170 level correlated significantly with the estimate of energy expenditure attributed to vigorous activities in the diabetic boys.

title: Alteration in sympathoadrenergic activity at rest and during intense exercise despite normal aerobic fitness in late pubertal adolescent girls with type 1 diabetes.
abstract: An impaired sympathoadrenergic response to hypoglycaemic episodes has been described in young Type 1 diabetic subjects. It is unknown if this altered response occurs with exercise, and if it could influence aerobic power.



Body composition (skinfold thickness), physical activity (questionnaire) and aerobic power (PWC170 and VO2max) were assessed in 19 post-menarcheal Type 1 diabetic (T1D) girls (13.3-18.2 years) and 19 healthy siblings. At rest and at each stage of the graded exhaustive exercise, plasma glucose, insulin, epinephrine and norepinephrine, were monitored via an intravenous catheter.



Only when expressed per kilograms of body weight, was aerobic power impaired in T1D girls compared to controls, probably because they were overweight. Throughout exercise, plasma glucose remained stable while plasma insulin decreased in the healthy girls, whereas glucose diminished significantly with no change in plasma insulin in T1D girls. During exercise catecholamines increased in the same way in both groups. However, at rest and throughout all stages of exercise, norepinephrine levels were significantly lower by a mean difference of 1.2 nmol/L, while epinephrine levels were significantly higher by a mean difference of 0.14 nmol/L, in T1D girls compared to healthy girls. Heart rates of T1D girls were not affected by the sympathoadrenergic alteration.



T1D adolescent girls display an altered sympathoadrenergic activity at rest and during intense exercise. Their reduced sympathetic activity, albeit probably compensated for by higher adrenomedullary responsiveness or sensitivity, does not affect their heart rate adaptations to exercise.

title: Fear of hypoglycaemia in parents of young children with type 1 diabetes: a systematic review
abstract: BackgroundMany children with type 1 diabetes have poor glycaemic control. Since the Diabetes Control and Complications Trial (DCCT) showed that tighter control reduces complication rates, there has been more emphasis on intensified insulin therapy. We know that patients and families are afraid of hypoglycaemia. We hypothesised that fear of hypoglycaemia might take precedence over concern about long-term complications, and that behaviour to avoid hypoglycaemia might be at the cost of poorer control, and aimed to evaluate the effectiveness of any interventions designed to prevent that. The objective of this review was to systematically review studies concerning the extent and consequences of fear of hypoglycaemia in parents of children under 12 years of age with type 1 diabetes, and interventions to reduce it. MEDLINE, EMBASE, PsycINFO, The Cochrane Library, Web of Science, meeting abstracts of EASD, ADA and Diabetes UK, Current Controlled Trials, ClinicalTrials.gov, UK CRN, scrutiny of bibliographies of retrieved papers and contact with experts in the field. Relevant studies of any design of parents of children under 12 years of age with Type 1 diabetes were included. The key outcomes were the extent and impact of fear, hypoglycaemia avoidance behaviour in parents due to parental fear of hypoglycaemia in their children, the effect on diabetes control, and the impact of interventions to reduce this fear and hypoglycaemia avoidance behaviour.ResultsEight articles from six studies met the inclusion criteria. All were cross sectional studies and most were of good quality. Parental fear of hypoglycaemia, anxiety and depression were reported to be common. There was a paucity of evidence on behaviour to avoid hypoglycaemia, but there were some suggestions that higher than desirable blood glucose levels might be permitted in order to avoid hypoglycaemia. No studies reporting interventions to reduce parental fear of hypoglycaemia were found. evidence base was limited. Parents of children with Type 1 diabetes reported considerable parental fear of hypoglycaemia, affecting both parental health and quality of life. There is some suggestion that hypoglycaemia avoidance behaviours by parents might adversely affect glycaemic control. Trials of interventions to reduce parental anxiety and hypoglycaemia avoidance behaviour are needed. We suggest that there should be a trial of structured education for parents of young children with Type 1 diabetes.

title: Fear of hypoglycaemia in adults with Type 1 diabetes
abstract: 27, 1151–1158 (2010)

title: Fear of Hypoglycemia in Parents of Young Children with Type 1 Diabetes Mellitus
abstract: The current study examined fear of hypoglycemia in 81 mothers and 64 fathers of young children with type 1 diabetes (T1DM) using the Hypoglycemia Fear Survey-Parents of Young Children (HFS-P-YC possible range = 26–130). Mothers and fathers completed the HFS-P-YC at enrollment and mothers completed it 2 weeks later. Families recorded daily blood glucose on a standardized meter for 2 weeks. Mothers’ mean total HFS-P-YC score was 75.0 (SD = 17.2) and fathers’ mean score was 66.5 (SD = 18.0). Mothers reported greater HFS-P-YC total and behavior subscale scores than fathers. Mothers’ HFS-P-YC scores were comparable to published HFS scores for mothers of preadolescents with T1DM and higher than adult patients with T1DM. The HFS-P-YC had good internal consistency and test–retest reliability in this sample. These findings suggest parents of young children with T1DM report a high level of fear of hypoglycemia. Additionally, the HFS-P-YC appears to be a reliable measure in this population.

title: Barriers to Physical Activity Among Patients With Type 1 Diabetes
abstract: To determine, in an adult population with type 1 diabetes, barriers to regular physical activity using a diabetes-specific barriers measure (the Barriers to Physical Activity in Diabetes [type 1] [BAPAD1] scale) and factors associated with these barriers. One hundred adults with type 1 diabetes answered a questionnaire assessing perceived barriers to physical activity and related factors. A1C was obtained from the medical chart of each individual. Fear of hypoglycemia was identified as being the strongest barrier to physical activity. Greater knowledge about insulin pharmacokinetics and using appropriate approaches to minimize exercise-induced hypoglycemia were factors associated with fewer perceived barriers. Greater barriers were positively correlated with A1C levels (r = 0.203; P = 0.042) and negatively with well-being (r = −0.45; P < 0.001). Fear of hypoglycemia is the strongest barrier to regular physical activity in adults with type 1 diabetes, who should therefore be informed and supported in hypoglycemia management.

title: Physical activity barriers in diabetes: development and validation of a new scale.
abstract: To develop and validate a questionnaire measuring perceived Barriers to Physical Activity in Diabetes (type 1) or BAPAD1. Initially, an open-ended questionnaire was filled by 36 patients. The modal accessible beliefs obtained on this pilot study were analysed and a scale composed of 12 items (BAPAD1) was developed and validated. Seventy-four type 1 diabetic patients filled the BAPAD1 scale. Cronbach alpha coefficient was 0.85 and the correlation between the test-retest scores was 0.84, both indicating adequate reliability of the barriers scale. Each item of BAPAD1 scale displayed very good item characteristic curve except for item 12, which was withdrawn. The test reliability curve indicated that the BAPAD1 scale is informative (value>or=0.82) at all levels of perceived barriers toward physical activity. Moreover, among diabetic-related items, the risk of hypoglycemia showed a particularly good item characteristic curve. In summary, the BAPAD1 scale presents excellent psychometric proprieties and among diabetic-related items, the risk of hypoglycemia should be considered as a significant target to overcome in order to increase physical activity. This new validated tool should be useful in identifying the most salient barriers toward the practice of physical activity and thus, permit more focused intervention in order to overcome those barriers.

title: Glycemic control in youth with diabetes: the SEARCH for diabetes in Youth Study.
abstract: To assess correlates of glycemic control in a diverse population of children and youth with diabetes.



This was a cross-sectional analysis of data from a 6-center US study of diabetes in youth, including 3947 individuals with type 1 diabetes (T1D) and 552 with type 2 diabetes (T2D), using hemoglobin A(1c) (HbA(1c)) levels to assess glycemic control.



HbA(1c) levels reflecting poor glycemic control (HbA(1c) >or= 9.5%) were found in 17% of youth with T1D and in 27% of those with T2D. African-American, American Indian, Hispanic, and Asian/Pacific Islander youth with T1D were significantly more likely to have higher HbA(1c) levels compared with non-Hispanic white youth (with respective rates for poor glycemic control of 36%, 52%, 27%, and 26% vs 12%). Similarly poor control in these 4 racial/ethnic groups was found in youth with T2D. Longer duration of diabetes was significantly associated with poorer glycemic control in youth with T1D and T2D.



The high percentage of US youth with HbA(1c) levels above the target value and with poor glycemic control indicates an urgent need for effective treatment strategies to improve metabolic status in youth with diabetes.

title: A1C in Children and Adolescents With Diabetes in Relation to Certain Clinical Parameters
abstract: We explored the relationship between A1C and insulin regimen, duration of diabetes, age, sex, and BMI as well as the differences between clinical mean A1C levels at pediatric diabetes clinics in Sweden. Data from 18,651 clinical outpatient visits (1,033 girls and 1,147 boys) at 20 pediatric clinics during 2001 and 2002 registered in the Swedish Childhood Diabetes Registry SWEDIABKIDS, a national quality registry, were analyzed. A1C was <7.0% (target value ∼8% per Diabetes Control and Complications Trial/National Glycohemoglobin Standardization Program standards) at 35% of the visits. Girls had significantly higher mean A1C than boys during adolescence. High mean A1C was correlated with high mean insulin dose, long duration of diabetes, and older age. Mean A1C varied between clinics (6.8–8.2%). Differences between centers could not be explained by differences in diabetes duration, age, BMI, or insulin dose. Adolescents with a high insulin dose and a long duration of diabetes, especially girls, need to be focused on. Differences in mean values between centers remained inexplicable and require further investigation.

title: Aortic Pulse-Wave Velocity and Its Relationship to Mortality in Diabetes and Glucose Intolerance: An Integrated Index of Vascular Function?
abstract: Arterial distensibility measures, generally from pulse-wave velocity (PWV), are widely used with little knowledge of relationships to patient outcome. We tested whether aortic PWV predicts cardiovascular and all-cause mortality in type 2 diabetes and glucose-tolerance–tested (GTT) multiethnic population samples. Participants were randomly sampled from (1) a type 2 diabetes outpatient clinic and (2) primary care population registers, from which nondiabetic control subjects were given a GTT. Brachial blood pressures and Doppler-derived aortic PWV were measured. Mortality data over 10 years’ follow-up were obtained. At any level of systolic blood pressure (SBP), aortic PWV was greater in subjects with diabetes than in controls. Mortality risk doubled in subjects with diabetes (hazard ratio 2.34, 95% CI 1.5 to 3.74) and in those with glucose intolerance (2.12, 95% CI 1.11 to 4.0) compared with controls. For all groups combined, age, sex, and SBP predicted mortality; the addition of PWV independently predicted all-cause and cardiovascular mortality (hazard ratio 1.08, 95% CI 1.03 to 1.14 for each 1 m/s increase) but displaced SBP. Glucose tolerance status and smoking were other independent contributors, with African-Caribbeans experiencing reduced mortality risk (hazard ratio 0.41, 95% CI 0.25 to 0.69). Aortic PWV is a powerful independent predictor of mortality in both diabetes and GTT population samples. In displacing SBP as a prognostic factor, aortic PWV is probably further along the causal pathway for arterial disease and may represent a useful integrated index of vascular status and hence cardiovascular risk.

title: Evidence based physical activity for school-age youth.
abstract: To review the effects of physical activity on health and behavior outcomes and develop evidence-based recommendations for physical activity in youth.



A systematic literature review identified 850 articles; additional papers were identified by the expert panelists. Articles in the identified outcome areas were reviewed, evaluated and summarized by an expert panelist. The strength of the evidence, conclusions, key issues, and gaps in the evidence were abstracted in a standardized format and presented and discussed by panelists and organizational representatives.



Most intervention studies used supervised programs of moderate to vigorous physical activity of 30 to 45 minutes duration 3 to 5 days per week. The panel believed that a greater amount of physical activity would be necessary to achieve similar beneficial effects on health and behavioral outcomes in ordinary daily circumstances (typically intermittent and unsupervised activity).



School-age youth should participate daily in 60 minutes or more of moderate to vigorous physical activity that is developmentally appropriate, enjoyable, and involves a variety of activities.

title: Influence of Adiposity and Physical Activity on Arterial Stiffness in Healthy Children: The Lifestyle of Our Kids Study
abstract: Childhood obesity is increasingly prevalent in the community and is related to adverse cardiovascular outcomes during adulthood. In this study of healthy children, we evaluated the influence of adiposity and physical activity on carotid-femoral pulse wave velocity (PWV), an index of arterial stiffness and a marker of cardiovascular risk in adults. In 573 community-based children (mean age: 10.1±0.3 years; 51% boys), we measured body mass index and waist circumference. Percentage body fat was quantitated by dual-energy x-ray absorptiometry. Cardiorespiratory fitness (CRF) and physical activity levels were assessed using a 20-m shuttle run and 7-day pedometer count, respectively. PWV was estimated by applanation tonometry. In univariate analysis, PWV was positively correlated with body mass index (r=0.34), waist circumference (r=0.32), and percentage body fat (r=0.32; P<0.001 for all) and negatively correlated with CRF (r=−0.23; P<0.001) and pedometer count (r=−0.08; P=0.046). In separate multivariable linear regression models, body mass index, waist circumference, and percentage of body fat were independently and positively associated with PWV (P<0.01 for all) after adjusting for age, sex, systolic blood pressure, mean arterial pressure, heart rate, and CRF (P<0.01 for all). The influence of CRF on PWV was attenuated after adjusting for adiposity. In conclusion, increased body mass and adiposity and decreased CRF are associated with arterial stiffening in healthy prepubescent children.

title: Influence of physical training on heart rate variability and baroreflex circulatory control.
abstract: Nineteen males (aged 45-68 yr) were studied before and after either a period of regular endurance exercise [walk/jog 3-4 days/wk for 30 +/- 1 (SE) wk, n = 11] or unchanged physical activity (38 +/- 2 wk, n = 8) (controls) to determine the influence of physical training on cardiac parasympathetic (vagal) tone and baroreflex control of heart rate (HR) and limb vascular resistance (VR) at rest in middle-aged and older men. Training resulted in a marked increase in maximal O2 uptake (31.6 +/- 1.2 vs. 41.0 +/- 1.8 ml.kg-1.min-1, 2.56 +/- 0.16 vs. 3.20 +/- 0.18 l/min, P less than 0.05) and small (P less than 0.05) reductions in body weight (81.2 +/- 3.5 vs. 78.7 +/- 4.0 kg) and body fat (23.8 +/- 1.3 vs. 20.9 +/- 1.3%). HR at rest was slightly, but consistently, lower after training (63 +/- 2 vs. 58 +/- 1 beats/min, P less than 0.05). In general, HR variability (index of cardiac vagal tone) was greater after training. Chronotropic responsiveness to either brief carotid baroreflex stimulation (neck suction) or inhibition (neck pressure), or to non-specific arterial baroreflex inhibition induced by a hypotensive level of lower body suction, was unchanged after training. In contrast, the magnitude of the reflex increase in forearm VR in response to three levels of lower body suction was markedly attenuated after training (38-59%; P less than 0.05 at -10 and -30 mmHg; P = 0.07 at -20 mmHg). None of these variables or responses was altered over time in the controls. These findings indicate that in healthy, previously sedentary, middle-aged and older men, strenuous and prolonged endurance training 1) elicits large increases in maximal exercise capacity and small reductions in HR at rest, 2) may increase cardiac vagal tone at rest, 3) does not alter arterial baroreflex control of HR, and 4) results in a diminished forearm vasoconstrictor response to reductions in baroreflex sympathoinhibition.

title: Heart rate variability in obese children: relations to total body and visceral adiposity, and changes with physical training and detraining.
abstract: Heart rate variability provides non-invasive information about cardiac parasympathetic activity (PSA). We determined in obese children: (1) relations of baseline PSA to body composition and hemodynamics; (2) effects of physical training (PT) and cessation of PT; and (3) which factors explained individual differences in responsivity of PSA to the PT.



The root mean square of successive differences (RMSSD) was the index of PSA. Obese children (n = 79) were randomly assigned to groups that participated in PT during the first or second 4-month periods of the study.



Baseline RMSSD was significantly (p<0.05) associated with lower levels of: fat mass, fat-free mass, subcutaneous abdominal adipose tissue, resting heart rate (HR), resting systolic blood pressure, and exercise HR. Stepwise multiple regression produced a final model (R2 = 0.36) that included only resting HR. The analysis of changes over the three time points of the study found a significant (p = 0.026) time by group interaction, such that RMSSD increased during periods of PT and decreased following cessation of PT. Greater individual increases in response to the PT (p<0.05) were seen in those who had lower pre-PT RMSSD levels, showed the greatest decreases in resting HR, and increased most in vigorous physical activity. The final regression model retained only the change in resting HR as a significant predictor of the changes in the RMSSD (R2 = 0.23).



Regular exercise that improved fitness and body composition had a favorable effect on PSA in obese children.

title: Heart rate variability in adolescents: relations to physical activity, fitness, and adiposity.
abstract: We determined the degree to which variation in cardiac autonomic modulation was explained by race, sex, moderate-vigorous physical activity (MVPA), cardiovascular fitness (CVF), percent body fat (%BF), waist girth, subcutaneous abdominal adipose tissue (SAAT), and visceral adipose tissue (VAT).



Subjects were 304 adolescents; SAAT and VAT values were available for 168 youths. Cardiac parasympathetic modulation (PM) was the root mean square of successive differences (RMSSD). Sympathetic-parasympathetic balance was the ratio of low- to high-frequency power (LFnu:HFnu). MVPA was measured with accelerometry, CVF with a treadmill, %BF with dual-energy x-ray absorptiometry (DXA), and SAAT and VAT with magnetic resonance imaging (MRI).



Root mean square of successive differences was higher, and LFnu:HFnu was lower, in blacks than in whites. The final regression model revealed positive relations with CVF and MVPA, and a %BF by race by sex interaction, such that higher %BF was associated with lower RMSSD in black females and higher RMSSD in white females. Higher RMSSD was associated with lower VAT; for SAAT, the relationship was negative for blacks and positive for whites. Hfnu, a negative relationship was seen with MVPA and higher waist girth was associated with a higher ratio in blacks, but not in whites. Both higher VAT and SAAT were related to higher LFnu:HFnu.



Black youths had a more favorable HRV profile than white youths. After controlling for age, race, and sex, more favorable HRV profiles were associated with more MVPA, better CVF, and less visceral and subcutaneous adiposity. The deleterious impact of higher adiposity was greater in blacks, especially females, than in whites. Enhancement of cardiac autonomic modulation may be a pathway through which physical activity, fitness, and leanness contribute to cardiovascular health early in life.

title: Habitual physical activity, physical fitness and heart rate variability in preadolescents.
abstract: The amount and type of physical activity (PA) appropriate in youth for optimal health is still being discussed. The purpose of this study on 12-year-old preadolescents is to evaluate the association of two PA patterns, corresponding to different exercise intensities, with some health-related indexes. PA was evaluated by triaxial accelerometry in 67 student subjects, who were successively classified according to 1) their usual participation or not in moderately intense (> 4 metabolic equivalents, METs) activities (either in daily life or in leisure activities) for at least 210 min a week (4 M (210)); and 2) the habitual practice or not of more intense activities (> 6 METs) for at least 60 min a week (6 M (60)). Health-related indexes consisted of cardiopulmonary (maximum oxygen uptake, V.O 2max), muscular (lower limb strength) fitness parameters and vagal-related indexes of heart rate (HR) variability (HRV), such as the HF/(LF+HF) ratio (where HF and LF stand for high and low frequency power). HR was recorded in the supine position after 15 min of quiet rest, and HRV indexes were calculated in 5-min segments. Energy expenditure due to PA was not significantly associated with any health-related index. Reaching 4 M (210) was associated with both higher estimated V.O 2max (p < 0.05) and higher muscular strength indexes (p < 0.05) but not with enhanced HRV indexes. Subjects who reached 6 M (60) had higher estimated V.O2max (p < 0.05) and higher HF/(LF+HF) (p < 0.05). Our results show that regular moderately intense activities are sufficient to influence physical fitness but suggest that more intense activities are necessary to observe more favorable HRV vagal-related indexes.

title: Physical fitness, dietary intake, and metabolic control in adolescents with type 1 diabetes
abstract: We examined whether physical fitness and dietary intake predicted better glycemic control and lipid profile in adolescents with type 1 diabetes mellitus (T1DM).