Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults Motivational counseling to reduce sitting time: a community-based randomized controlled trial in adults. Objective vs. Self-Reported Physical Activity and Sedentary Time: Effects of Measurement Method on Relationships with Risk Biomarkers Total Worker Health Intervention Increases Activity of Sedentary Workers. Sedentary time and markers of inflammation in people with newly diagnosed type 2 diabetes Effects of a DVD-delivered exercise program on patterns of sedentary behavior in older adults: a randomized controlled trial☆☆☆ Impact of objectively measured sedentary behaviour on changes in insulin resistance and secretion over 3 years in the RISC study: interaction with weight gain. Is Objectively Assessed Sedentary Behavior, Physical Activity and Cardiorespiratory Fitness Linked to Brain Plasticity Outcomes in Old Age? Plasma vitamin D is associated with fasting insulin and homeostatic model assessment of insulin resistance in young adult males, but not females, of the Jerusalem Perinatal Study. Accelerometer-measured dose-response for physical activity, sedentary time, and mortality in US adults. Participatory Workplace Interventions Can Reduce Sedentary Time for Office Workers—A Randomised Controlled Trial What are the most effective behaviour change techniques to promote physical activity and/or reduce sedentary behaviour in inactive adults? A systematic review protocol Replacing sedentary time with sleep, light, or moderate-to-vigorous physical activity: effects on self-regulation and executive functioning A comparison of work-related physical activity levels between inpatient and outpatient physical therapists: an observational cohort trial Performance of thigh-mounted triaxial accelerometer algorithms in objective quantification of sedentary behaviour and physical activity in older adults Evaluation of the UP4FUN Intervention: A Cluster Randomized Trial to Reduce and Break Up Sitting Time in European 10-12-Year-Old Children Associations Between Sedentary Behaviors and Cognitive Function: Cross-Sectional and Prospective Findings From the UK Biobank A longitudinal study of sedentary behavior and overweight in adolescent girls. Higher levels of objectively measured sedentary behavior is associated with worse cognitive ability: Two-year follow-up study in community-dwelling older adults Development of a questionnaire to assess sedentary time in older persons – a comparative study using accelerometry Sitting Behavior and Obesity Too much sitting: the population health science of sedentary behavior. Objectively measured physical activity and sedentary time: cross-sectional and prospective associations with adiposity in the Millennium Cohort Study
Adults are sedentary for an alarming 9 to 10 hours per day ( 1 ) . Accordingly , the popular press has coined the phrase sitting is the new smoking to describe a current epidemic of developed nations ( 24 ) . Evidence indicates that sedentary time is associated with incident cardiovascular disease , incidence of cardiovascular diseaserelated risk factors , and mortality ( 5 , 6 ) . Of note , the risk conferred by prolonged sedentariness is eliminated only by high levels of moderate- to vigorous-intensity physical activity ( MVPA ) ( about 60 to 75 min/d ) , which exceed physical activity recommendations ( 7 , 8) . As such , sedentary behavior is now believed to represent a clinical ly important aspect of a person 's physical activity profile and is no longer considered simply the extreme low end of the physical activity continuum ( 5 ) . Studies linking sedentary behavior to health outcomes have relied almost exclusively on self-reported  sedentary time  , which is subject to reporting bias and measurement error ( 9 ) . A 2015 systematic review ( 5 ) identified only 1 study ( NHANES [ National Health and Nutrition Examination Survey ] ) that examined the association between objective ly measured sedentary time and health outcomes , a study limited by a small event rate ( 10 ) . New studies using NHANES data have since been published , with longer follow-up and higher event rates ( 1115 ) . However , some of these studies have reported an association between objective ly measured sedentary time and mortality ( 11 , 14 , 15 ) , but others have not ( 12 , 13 ) . Additional cohort studies are thus needed to rectify evidence gaps . Furthermore , studies using accelerometers to objective ly measure sedentary behavior conventionally operationalize sedentary time as the total number of sedentary minutes per day . This approach ignores patterns of accumulated sedentary behavior over time . For example , accumulation of sedentary time in a few long bouts or many short bouts represents 2 distinct patterns of sedentary time accrual . Experimental studies have shown that acute periods of prolonged , uninterrupted sedentary behavior cause greater detrimental cardiometabolic effects than sedentary behavior that is periodically interrupted ( 1618 ) , suggestive that it is not just total sedentary time that is relevant to health outcomes , but also the manner in which it is accumulated . Few longitudinal studies , however , have explored the association between prolonged , uninterrupted sedentary behavior and mortality to corroborate these findings . To inform guidelines on reducing sedentary behavior ( target reductions in overall sedentary time or target interruption of prolonged sedentary bouts ) , evidence from prospect i ve studies is needed to 1 ) confirm the association between total sedentary time and mortality using objective measures , 2 ) determine whether prolonged sedentary bouts confer risk for death , and 3 ) eluci date whether the total volume of sedentary time and its pattern of accumulation individually or jointly contribute to risk for death . The purpose of this study , therefore , was to examine the association between objective ly measured sedentary time ( both total volume and accrual in prolonged bouts ) and all-cause mortality in a national cohort of U.S. middle-aged and older adults enrolled in the REGARDS ( Reasons for Geographic and Racial Differences in Stroke ) study . Methods Study Population REGARDS is a population -based study design ed to examine racial and regional disparities in stroke . It comprises 30239 white and black adults aged 45 years or older enrolled between 2003 and 2007 from across the contiguous United States ( 19 , 20 ) . Detailed design and methods for REGARDS are described elsewhere ( 21 ) . Briefly , demographic and cardiovascular risk factor data were collected by telephone interview and an in-home physical assessment on enrollment . A detailed summary of baseline measures is provided in the Supplement . Participants ( or their proxies ) were then followed for 6-month intervals to ascertain vital status . Objective measurements of sedentary behavior were collected from active REGARDS participants from 2009 to 2013 ( mean time from study enrollment , 5.7 years [ SD , 1.5 ] ; range , 1.9 to 9.5 years ) ( 22 ) . A total of 7985 participants adhered to accelerometer wear requirements ( 4 days with accelerometer wear 10 hours ) , provided follow-up data , and were available for the current analyses ( Supplement Figure 1 ) . Supplement Table 1 shows the characteristics of included versus excluded REGARDS participants . The REGARDS study protocol was approved by the institutional review boards of participating institutions . All participants provided informed consent . Supplement . Supplementary Material Accelerometer Data Collection Methods for accelerometer data collection are described elsewhere ( 22 ) . Briefly , participants were fitted with an Actical ( Philips Respironics ) accelerometer secured to their right hip using a nylon belt and were instructed to wear the device during waking hours for 7 consecutive days . The Actical had been vali date d formeasurement of physical activity and sedentary behavior and was shown to have acceptable reliability ( 2325 ) . Activity counts were summed over 1-minute epochs . Nonwear periods were defined as at least 150 consecutive minutes of 0 activity counts . This nonwear algorithm was previously vali date d against daily log sheets in REGARDS participants ( 26 ) . Measurements of 0 to 49 , 50 to 1064 , and at least 1065 counts per minute were defined as sedentary behavior , light-intensity physical activity , and MVPA , respectively , as determined in a laboratory-based calibration study ( 27 ) . A sedentary bout was defined as consecutive minutes in which the accelerometer registered fewer than 50 counts per minute . A sedentary break was defined as at least 1 minute in which 50 or more counts per minute were registered after a sedentary bout . Both sedentary bouts and breaks were exclusively continuous periods , with no interruptions or nonwear intervals allowed in the definition . Outcome Ascertainment All-cause mortality was the primary outcome , defined as any death after completion of the accelerometer protocol regardless of cause . Date s of death were confirmed through review of death certificates , medical records , and administrative data bases . Deaths through 4 September 2015 were included in the current analysis . Statistical Analysis Sedentary and physical activity variables were averaged across compliant days ( 10 hours of wear ) . Because of a high correlation between total sedentary time and wear time ( Supplement Figure 2 ) , we corrected for the influence of wear time by st and ardizing total sedentary time to 16 hours of wear time per day using the residuals obtained when regressing total sedentary time on wear time ( see Methods section of the Supplement ) ( 2830 ) . Participants were stratified into quartiles according to total sedentary time and , separately , mean sedentary bout duration ( a measure of overall prolonged , uninterrupted sedentary behavior ) . Cox proportional hazards regression modeling was used to calculate the hazard ratio ( HR ) for all-cause mortality associated with quartiles of total sedentary time ( and separately , mean sedentary bout length ) . Crude HRs were initially calculated . Subsequent HRs were calculated after adjustment for age , race , sex , region of residence , education , and season the accelerometer was worn ( model 1 ) , with further adjustment for current smoking , alcohol use , body mass index ( BMI ) , diabetes , hypertension , dyslipidemia , estimated glomerular filtration rate less than 60 mL/min/1.73 m2 , atrial fibrillation , history of coronary heart disease , and history of stroke ( model 2 ) . Models were additionally adjusted for MVPA expressed continuously ( model 3 ) . Tests for linear trend across quartiles were conducted by including the quartile for each participant as an ordinal variable in regression models . Proportional hazards assumptions were confirmed with a Kolmogorov-type supremum test ( 31 ) . The above analyses were then repeated in a fully adjusted model , testing interactions for age ( < 65 and 65 years ) , sex ( male and female ) , race ( black and white ) , BMI category ( normal weight and overweight or obese ) , and MVPA category ( < 150 min/wk and 150 min/wk ) . As a secondary analysis , we examined the continuous doseresponse relationship between each sedentary characteristic and all-cause mortality in a fully adjusted model ( model 3 ) using restricted cubic splines ( 32 ) . Cubic polynomials were fitted with the mean of each sedentary characteristic set as the reference and knots placed at the 5th , 35th , 65th , and 95th percentiles ( 33 ) . Nonlinear associations were evaluated using the likelihood ratio test . For nonlinear associations , spline models were used to describe the associations and when the association was determined to be linear , a linear model was used . Because of multicollinearity between total sedentary time and mean sedentary bout duration ( r= 0.61 ) , both variables were not included in the same model . Alternatively , to examine the individual and joint associations of total sedentary time and prolonged , uninterrupted sedentary behavior with mortality , participants were classified into 4 categories : low total sedentary time ( < 750 min/d ) and low prolonged sedentary bout time ( < 10 min/bout ) , low total sedentary time  and high prolonged sedentary bout time  ( 10 min/bout ) , high total sedentary time  ( 750 min/d ) and low prolonged sedentary bout time , and high total sedentary time and high prolonged sedentary bout time . Hazard ratios for all-cause mortality were calculated for each joint category in comparison with the lowlow group in a fully adjusted model ( model 3 ) . Thresholds for total sedentary time ( 750 min/d ) and mean sedentary bout duration ( 10 min/bout ) were selected on the basis of the restricted cubic splines and were confirmed using a method described by Contal and O'Quigley ( see Methods section of the Supplement ) ( 34 ) . To allow for the possibility that sedentary bouts BACKGROUND Sedentary behavior is regarded as a distinct risk factor for cardiometabolic morbidity and mortality , but knowledge of the efficacy of interventions targeting reductions in sedentary behavior is limited . PURPOSE To investigate the effect of an individualized face-to-face motivational counseling intervention aim ed at reducing sitting time . DESIGN A r and omized , controlled , observer-blinded , community-based trial with two parallel groups using open-end r and omization with 1:1 allocation . SETTING / PARTICIPANTS A total of 166 sedentary adults were consecutively recruited from the population -based Health2010 Study . INTERVENTION Participants were r and omized to a control ( usual lifestyle ) or intervention group with four individual theory-based counseling sessions . MAIN OUTCOME MEASURES Objective ly measured overall sitting time ( ActivPAL 3TM , 7 days ) ; secondary measures were breaks in sitting time , anthropometric measures , and cardiometabolic biomarkers , assessed at baseline and after 6 months . Data were collected in 2010 - 2012 and analyzed in 2013 - 2014 using repeated measures multiple regression analyses . RESULTS Ninety-three participants were r and omized to the intervention group and 73 to the control group , and 149 completed the study . The intervention group had a mean sitting time decrease of -0.27 hours/day , corresponding to 2.9 % of baseline sitting time ( hours/day ) ; the control group increased mean sitting time by 0.06 hours/day . The between-group difference in change , -0.32 hours/day ( 95 % CI=-0.87 , 0.24 , p=0.26 ) , was not statistically significant . Significant differences in change in fasting serum insulin of -5.9 pmol/L ( 95 % CI=-11.4 , -0.5 , p=0.03 ) ; homeostasis model assessment -estimated insulin resistance of -0.28 ( 95 % CI=-0.53 , -0.03 , p=0.03 ) ; and waist circumference of -1.42 cm ( 95 % CI=-2.54 , -0.29 , p=0.01 ) were observed in favor of the intervention group . CONCLUSIONS Although the observed decrease in sitting time was not significant , a community-based , individually tailored , theory-based intervention program aim ed at reducing sitting time may be effective for increasing st and ing and improving cardiometabolic health in sedentary adults . TRIAL REGISTRATION This study is registered at Clinical trials.gov ( NCT00289237 ) Purpose Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes . We aim ed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and question naire-based activity measures . Methods  Physical activity and sedentary behaviour  were assessed in 317 adults by 7-day accelerometry and International Physical Activity Question naire ( IPAQ ) . Fasting blood was taken to determine insulin , glucose , triglyceride and total , LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance ( HOMAIR ) . Waist circumference , BMI , body fat percentage and blood pressure were also measured . Results For both accelerometer-derived sedentary time ( < 100 counts.min−1 ) and IPAQ-reported sitting time significant positive ( negative for HDL cholesterol ) relationships were observed with all measured risk factors – i.e. increased sedentary behaviour was associated with increased risk ( all p≤0.01 ) . However , for HOMAIR and insulin the regression coefficients were > 50 % lower for the IPAQ-reported compared to the accelerometer-derived measure ( p<0.0001 for both interactions ) . The relationships for moderate-to-vigorous physical activity ( MVPA ) and risk factors were less strong than those observed for sedentary behaviours , but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose , and insulin and HOMAIR values ( all p<0.05 ) . For accelerometer-derived MVPA only , additional negative relationships were seen with triglyceride , total cholesterol and LDL cholesterol concentrations , BMI , waist circumference and percentage body fat , and a positive relationship was evident with HDL cholesterol ( p = 0.0002 ) . Regression coefficients for HOMAIR , insulin and triglyceride were 43–50 % lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure ( all p≤0.01 ) . Conclusion Using the IPAQ to determine sitting time and MVPA reveals some , but not all , relationships between these activity measures and metabolic and vascular disease risk factors . Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors INTRODUCTION Office employees are exposed to hazardous levels of sedentary work . Interventions that integrate health promotion and health protection elements are needed to advance the health of sedentary workers . This study tested an integrated intervention on occupational sedentary/physical activity behaviors , cardiometabolic disease biomarkers , musculoskeletal discomfort , and work productivity . DESIGN Two-group , RCT . Data were collected between January and August 2014 . SETTING / PARTICIPANTS Overweight/obese adults working in sedentary desk jobs were r and omized to : ( 1 ) a health protection-only group ( HPO , n=27 ) ; or ( 2 ) an integrated health protection/health promotion group ( HP/HP , n=27 ) . INTERVENTION HPO participants received an ergonomic workstation optimization intervention and three e-mails/week promoting rest breaks and posture variation . HP/HP participants received the HPO intervention plus access to a seated activity permissive workstation . MAIN OUTCOME MEASURES Occupational sedentary and physical activity behaviors ( primary outcomes ) , cardiometabolic health outcomes , musculoskeletal discomfort , and work productivity ( secondary outcomes ) were measured at baseline and post-intervention ( 16 weeks ) . RESULTS The HP/HP group increased occupational light intensity physical activity over the HPO group and used the activity permissive workstations 50 minutes/work day . Significant associations were observed between activity permissive workstation adherence and improvements in several cardiometabolic biomarkers ( weight , total fat mass , resting heart rate , body fat percentage ) and work productivity outcomes ( concentration at work , days missed because of health problems ) . CONCLUSIONS The HP/HP group increased occupational physical activity and greater activity permissive workstation adherence was associated with improved health and work productivity outcomes . These findings are important for employers interested in advancing the well-being of sedentary office workers . TRIAL REGISTRATION This study is registered at www . clinical trials.gov NCT02071420 Background and aims We investigated whether objective ly measured sedentary time was associated with markers of inflammation in adults with newly diagnosed type 2 diabetes . Methods and results We studied 285 adults ( 184 men , 101 women , mean age 59.0 ± 9.7 ) who had been recruited to the Early ACTivity in Diabetes ( Early ACTID ) r and omised controlled trial .  C-reactive protein ( CRP ) , adiponectin , soluble intracellular adhesion molecule-1 ( sICAM-1 ) , interleukin-6 ( IL-6 ) , and accelerometer-determined sedentary time and moderate-vigorous physical activity ( MVPA ) were measured at baseline and after six-months . Linear regression analysis was used to investigate the independent cross-sectional and longitudinal associations of sedentary time  with markers of inflammation . At baseline , associations between sedentary time and IL-6 were observed in men and women , an association that was attenuated following adjustment for waist circumference . After 6 months of follow-up  , sedentary time was reduced by 0.4 ± 1.2 h per day in women , with the change in sedentary time predicting CRP at follow-up . Every hour decrease in sedentary time  between baseline and six-months was associated with 24 % ( 1 , 48 ) lower CRP . No changes in sedentary time between baseline and 6 months were seen in men . Conclusions  Higher sedentary time  is associated with IL-6 in men and women with type 2 diabetes , and reducing sedentary time is associated with improved levels of CRP in women . Interventions to reduce sedentary time may help to reduce inflammation in women with type 2 diabetes Introduction In the present study , we examined the influence of a home-based , DVD-delivered exercise intervention on daily sedentary time and breaks in sedentary time in older adults . Methods Between 2010 and 2012 , older adults ( i.e. , aged 65 or older ) residing in Illinois ( N = 307 ) were r and omized into a 6-month home-based , DVD-delivered exercise program ( i.e. , FlexToBa ; FTB ) or a waitlist control . Participants completed measurements prior to the first week ( baseline ) , following the intervention period ( month 6 ) , and after a 6 month no-contact follow-up ( month 12 ) . Sedentary behavior was measured objective ly using accelerometers for 7 consecutive days at each time point . Differences in daily sedentary time and breaks between groups and across the three time points were examined using mixed-factor analysis of variance ( mixed ANOVA ) and analysis of covariance ( ANCOVA ) . Results Mixed ANOVA models revealed that daily minutes of sedentary time did not differ by group or time . The FTB condition , however , demonstrated a greater number of daily breaks in sedentary time relative to the control condition ( p = .02 ) . ANCOVA models revealed a non-significant effect favoring FTB at month 6 , and a significant difference between groups at month 12 ( p = .02 ) . Conclusions While overall sedentary time did not differ between groups , the DVD-delivered exercise intervention was effective for maintaining a greater number of breaks when compared with the control condition . Given the accumulating evidence emphasizing the importance of breaking up sedentary time , these findings have important implication s for the design of future health behavior interventions AIMS The importance of reducing sedentary time is increasingly being recognized in the prevention of diabetes and cardiovascular disease . Despite this , the prospect i ve association between sedentary time and physical activity with insulin sensitivity and cardiometabolic risk factors has been little studied . METHODS In an analysis of data from the European RISC study , sedentary time and time spent in activity of moderate or vigorous intensity were assessed by accelerometry at baseline in 313 men and 414 women , aged 30 - 60 years , with insulin sensitivity as measured by euglycaemic-hyperinsulinaemic clamp . Three years later , cardiometabolic risk factors ( anthropometry , glucose , insulin , lipids ) were available for 549 participants . RESULTS In cross-sectional analyses using baseline data , after adjusting for age , gender , recruitment centre and time spent in activity of moderate or vigorous intensity , significant unfavourable associations were observed between higher sedentary time with body weight , HDL cholesterol , triglycerides , clamp-measured insulin sensitivity and insulin secretion ( all P(trend)<0.002 ) .  Sedentary time  remained significantly associated with insulin secretion after adjusting for insulin sensitivity ( P(trend)=0.02 ) . In longitudinal analyses , higher baseline sedentary time  was associated with 3-year increases in fasting glucose , fasting insulin and the HOMA insulin-resistance index score for the 50 % of the study population who increased their BMI by at least 0.3 kg/m(2 ) ( all P(trend)<0.01 ) ; these relationships remained significant after adjusting for time spent in activity of moderate or vigorous intensity . The 3-year increase in insulin secretion was lower in those spending more time doing activity of moderate or vigorous intensity ( P(trend)=0.03 ) . CONCLUSION These prospect i ve data suggest that less sedentary behaviour may partly counteract some of the negative effects of increasing body weight on glucose-insulin homoeostasis The aim of this cross-sectional study was to determine the associations of objective ly assessed habitual physical activity and physical performance with brain plasticity outcomes and brain-derived neurotrophic factor ( BDNF ) levels in cognitively healthy older adults . Physical performance was analyzed based on cardiopulmonary exercise-testing data and accelerometer-based physical activity was analyzed as total activity counts , sedentary time , light physical activity and moderate to vigorous physical activity . Brain plasticity outcomes included magnetic resonance spectroscopy (MRS)-based markers , quantitative imaging-based hippocampal volume and BDNF serum levels . The association between physical performance and hippocampal volume was strongly influenced by participants ' education , sex , age and BMI . Confounder-controlled correlation revealed significant associations of brain plasticity outcomes with physical activity but not with performance . MRS-based adenosine triphosphate to phosphocreatine and glycerophosphocholine to phosphocreatine ratios were significantly associated with accelerometer total activity counts . BDNF was detrimentally associated with sedentary time but beneficially related to  accelerometer total activity  counts and moderate to vigorous physical activity . Exceeding the current moderate to vigorous physical activity recommendations led to significantly higher BDNF levels . Our results indicate that regular physical activity might be beneficial for preserving brain plasticity in higher age . In this study these associations were not mediated significantly by physical performance . Overall physical activity and exceeding current moderate to vigorous physical activity recommendations were positively associated with BDNF . Sedentary behavior , however , seems to be negatively related to neurotrophic factor bioavailability in the elderly OBJECTIVE To examine cross-sectional relationships between plasma vitamin D and cardiometabolic risk factors in young adults . DESIGN Data were collected from interviews , physical examinations and biomarker measurements . Total plasma 25-hydroxyvitamin D ( 25(OH)D ) was measured using LC-t and em MS . Associations between 25(OH)D and cardiometabolic risk factors were modelled using weighted linear regression with robust estimates of st and ard errors . SETTING Individuals born in Jerusalem during 1974 - 1976 . SUBJECTS Participants of the Jerusalem Perinatal Study ( n 1204 ) interviewed and examined at age 32 years . Participants were over sample d for low and high birth weight and for maternal pre-pregnancy obesity .  RESULTS Mean total 25(OH)D concentration among participants was 21·7 ( sd 8·9 ) ng/ml . Among males , 25(OH)D was associated with homeostatic model assessment of insulin resistance ( natural log-transformed , β=-0·011 , P=0·004 ) after adjustment for BMI . However , these associations were not present among females ( P for sex interaction=0·005 ) . CONCLUSIONS We found evidence for inverse associations of 25(OH)D with markers of insulin resistance among males , but not females , in a healthy , young adult Caucasian population . Prospect i ve studies and studies conducted on other population s investigating sex-specific effects of vitamin D on cardiometabolic risk factors are warranted BACKGROUND Moderate-to-vigorous-intensity physical activity is recommended to maintain and improve health , but the mortality benefits of light activity and risk for sedentary time remain uncertain . OBJECTIVES Using accelerometer-based measures , we 1 ) described the mortality dose-response for sedentary time and light- and moderate-to-vigorous-intensity activity using restricted cubic splines , and 2 ) estimated the mortality benefits associated with replacing sedentary time with physical activity , accounting for total activity . DESIGN US adults ( n = 4840 ) from NHANES ( 2003 - 2006 ) wore an accelerometer for ≤7 d and were followed prospect ively for mortality . Proportional hazards models were used to estimate adjusted HRs and 95 % CIs for mortality associations with time spent sedentary and in light- and moderate-to-vigorous-intensity physical activity . Splines were used to graphically present behavior-mortality relation . Isotemporal models estimated replacement associations for sedentary time , and separate models were fit for low- ( < 5.8 h total activity/d ) and high-active participants to account for nonlinear associations . RESULTS Over a mean of 6.6 y , 700 deaths occurred . Compared with less-sedentary adults ( 6 sedentary h/d ) , those who spent 10 sedentary h/d had 29 % greater risk ( HR : 1.29 ; 95 % CI : 1.1 , 1.5 ) . Compared with those who did less light activity ( 3 h/d ) , those who did 5 h of light activity/d had 23 % lower risk ( HR : 0.77 ; 95 % CI : 0.6 , 1.0 ) . There was no association with mortality for sedentary time or light or moderate-to-vigorous activity in highly active adults . In less-active adults , replacing 1 h of sedentary time with either light- or moderate-to-vigorous-intensity activity was associated with 18 % and 42 % lower mortality , respectively . CONCLUSIONS Health promotion efforts for physical activity have mostly focused on moderate-to-vigorous activity . However , our findings derived from accelerometer-based measurements suggest that increasing light-intensity activity and reducing sedentary time are also important , particularly for inactive adults Background Occupational sedentary behaviour is an important contributor to overall sedentary risk . There is limited evidence for effective workplace interventions to reduce occupational sedentary time and increase light activity during work hours . The purpose of the study was to determine if participatory workplace interventions could reduce total sedentary time , sustained sedentary time ( bouts > 30 minutes ) , increase the frequency of breaks in sedentary time and promote light intensity activity and moderate/vigorous activity ( MVPA ) during work hours . Methods A r and omised controlled trial ( ANZCTR number : ACTN12612000743864 ) was conducted using clerical , call centre and data processing workers ( n = 62 , aged 25–59 years ) in 3 large government organisations in Perth , Australia . Three groups developed interventions with a participatory approach : ‘ Active office ’ ( n = 19 ) , ‘ Active Workstation ’ and promotion of incidental office activity ; ‘ Traditional physical activity ’ ( n = 14 ) , pedometer challenge to increase activity between productive work time and ‘ Office ergonomics ’ ( n = 29 ) , computer workstation design and breaking up computer tasks . Accelerometer ( ActiGraph GT3X , 7 days ) determined sedentary time , sustained sedentary time , breaks in sedentary time , light intensity activity and MVPA on work days and during work hours were measured before and following a 12 week intervention period . Results For all participants there was a significant reduction in sedentary time on work days ( −1.6 % , p = 0.006 ) and during work hours ( −1.7 % , p = 0.014 ) and a significant increase in number of breaks/sedentary hour on work days ( 0.64 , p = 0.005 ) and during work hours ( 0.72 , p = 0.015 ) ; there was a concurrent significant increase in light activity during work hours ( 1.5 % , p = 0.012 ) and MVPA on work days ( 0.6 % , p = 0.012 ) . Conclusions This study explored novel ways to modify work practice s to reduce occupational sedentary behaviour . Participatory workplace interventions can reduce sedentary time , increase the frequency of breaks and improve light activity and MVPA of office workers by using a variety of interventions . Trial Registration Australian New Zeal and Clinical Trials Registry ACTN12612000743864 Introduction Large proportions of the population are not meeting recommended levels of physical activity and have increasingly sedentary lifestyles . Low levels of physical activity are predictive of poor health outcomes and time spent sedentary is related to a host of risk factors independently of physical activity levels . Building an evidence base of the best approaches to intervene in the lifestyles of inactive individuals is crucial in preventing long-term disease , disability and higher mortality rates . Methods and analysis Systematic search es will be conducted on all relevant data bases ( eg , PubMed , Scopus , CINAHL , PsycINFO ) . Studies will be included if they assess interventions aim ed at changing physical activity or sedentary behaviour levels in adults ( over 18 ) who are inactive and do not suffer from chronic conditions . Studies must also be r and omised controlled trials ( RCTs ) , have a primary outcome of physical activity or sedentary behaviour , and measure outcomes at least 6 months after intervention completion . Studies will be coded using the Behaviour Change Technique ( BCT ) taxonomy v1 and Template for Intervention Description and Replication ( TIDieR ) guidelines . 2 review ers will independently screen full-text articles and extract data on study characteristics , participants , BCTs , intervention features and outcome measures . Study quality will also be assessed independently by 2 review ers using the Cochrane risk of bias tool . A meta- analysis will be considered if there is sufficient homogeneity across outcomes . GRADE criteria will be used to assess quality of evidence . Dissemination This will be the first review to systematic ally appraise interventions aim ed at changing the physical activity or sedentary behaviour of inactive individuals using RCT design s with a 6-month follow-up post-intervention . This review will better inform intervention design ers targeting inactive population s and inform the design of a future complex intervention . Review registration number This protocol was registered with the International Prospect i ve Register of Systematic Review s ( PROSPERO ) on 17 October 2014 ( registration number : CRD42014014321 ) Abstract Recent attention has highlighted the importance of reducing sedentary time for maintaining health and quality of life . However , it is unclear how changing sedentary behavior may influence executive functions and self-regulatory strategy use , which are vital for the long-term maintenance of a health behavior regimen . The purpose of this cross-sectional study is to examine the estimated self-regulatory and executive functioning effects of substituting 30 min of sedentary behavior with 30 min of light activity , moderate-to-vigorous physical activity ( MVPA ) , or sleep in a sample of older adults . This study reports baseline data collected from low-active healthy older adults ( N = 247 , mean age 65.4 ± 4.6 years ) recruited to participate in a 6 month r and omized controlled exercise trial examining the effects of various modes of exercise on brain health and function . Each participant completed assessment s of  physical activity self-regulatory strategy use ( i.e. ,  self-monitoring , goal - setting , social support , reinforcement , time management , and relapse prevention )  and executive functioning . Physical activity and sedentary behaviors  were measured using accelerometers during waking hours for seven consecutive days at each time point . Isotemporal substitution analyses were conducted to examine the effect on self-regulation and executive functioning should an individual substitute sedentary time with light activity , MVPA , or sleep . The substitution of sedentary time with both sleep and MVPA influenced both self-regulatory strategy use and executive functioning . Sleep was associated with greater self-monitoring ( B = .23 , p = .02 ) , goal - setting ( B = .32 , p < .01 ) , and social support ( B = .18 , p = .01 ) behaviors . Substitution of sedentary time with MVPA was associated with higher accuracy on 2-item ( B = .03 , p = .01 ) and 3-item ( B = .02 , p = .04 ) spatial working memory tasks , and with faster reaction times on single ( B = −23.12 , p = .03 ) and mixed-repeated task-switching blocks ( B = −27.06 , p = .04 ) . Substitution of  sedentary  time with sleep was associated with marginally faster reaction time on mixed-repeated task-switching blocks ( B = −12.20 , p = .07 ) and faster reaction time on mixed-switch blocks ( B = 17.21 , p = .05 ) , as well as reduced global reaction time switch cost ( B = −16.86 , p = .01 ) . Substitution for light intensity physical activity did not produce significant effects . By replacing sedentary time with sleep and MVPA , individuals may bolster several important domains of self-regulatory behavior and executive functioning . This has important implication s for the design of long-lasting health behavior interventions . Trial Registration clinical trials.gov identifier NCT00438347 Background  Physical therapists ( PTs ) work in a variety of healthcare setting s with varied levels of physical activity dem and s placed on them . The purpose of this study is to compare the  physical activity ( PA ) levels between PTs in inpatient versus outpatient environments for one work week using a cross-sectional design . Methods Sixty-one PTs ( 30 inpatient , 31 outpatient ) wore a tri-axial accelerometer and inclinometer for one work-week . The number steps-per-day , PA intensities , energy expenditures and postural positions adopted during the work day were recorded . ResultS ignificantly longer amounts of time spent sitting was found for inpatient PTs regardless of the significantly higher number of steps-per-day . Outpatient PTs had a higher number of breaks from sedentary activity with those breaks being longer than the inpatient PTs . The percentage of time spent performing moderate-vigorous PA approached significance implying more time was spent performing these types of activities for outpatient PTs . The energy expenditures between the two groups of PTs were not different . Conclusion This study compared the differences in physical activity levels between physical therapists who worked at inpatient versus outpatient environment as little is known about their activity levels . Inpatient physical therapists took more steps per day than outpatient physical therapists but the outpatient physical therapists were less sedentary and took more frequent and longer breaks from sedentary activities . The energy expenditures were similar between both types of therapists and this may be reflective of the gender and bodyweight differences between the groups that equalizes the energy expenditures . The findings of this study suggests that there are differences in the physical activity dem and s between inpatient and outpatient physical therapists . The results of this study may serve dual purpose s : ( 1 ) employers may be able to more accurately describe the expected physical activity dem and s to future employees ; ( 2 ) individuals tasked with preparing PTs to physically manage their work environment can outline training programs that are diverse based on the specific work environment of PTs Accurate monitoring of sedentary behaviour and physical activity is key to investigate their exact role in healthy ageing . To date , accelerometers using cut-off point models are most preferred for this , however , machine learning seems a highly promising future alternative . Hence , the current study compared between cut-off point and machine learning algorithms , for optimal quantification of sedentary behaviour and physical activity intensities in the elderly . Thus , in a heterogeneous sample of forty participants ( aged ≥60 years , 50 % female ) energy expenditure during laboratory-based activities ( ranging from sedentary behaviour through to moderate-to-vigorous physical activity ) was estimated by indirect calorimetry , whilst wearing triaxial thigh-mounted accelerometers . Three cut-off point algorithms and a R and om Forest machine learning model were developed and cross-vali date d using the collected data . Detailed analyses were performed to check algorithm robustness , and examine and benchmark both overall and participant-specific balanced accuracies . This revealed that the four models can at least be used to confidently monitor sedentary behaviour and moderate-to-vigorous physical activity . Nevertheless , the machine learning algorithm outperformed the cut-off point models by being robust for all individual ’s physiological and non-physiological characteristics and showing more performance of an acceptable level over the whole range of physical activity intensities . Therefore , we propose that R and om Forest machine learning may be optimal for objective assessment of sedentary behaviour and physical activity in older adults using thigh-mounted triaxial accelerometry Background The UP4FUN intervention is a family-involved school-based intervention aim ing at reducing and breaking up sitting time at home ( with special emphasis on screen time ) , and breaking up sitting time in school among 10–12 year olds in Europe . The purpose of the present paper was to evaluate its short term effects . Methodology /Principal Findings A total of 3147 pupils from Belgium , Germany , Greece , Hungary and Norway participated in a school-r and omized controlled trial . The intervention included 1–2 school lessons per week for a period of six weeks , along with assignments for the children and their parents . Screen time and breaking up sitting time were registered by self-report and total sedentary time and breaking up sitting time by accelerometry . The effect of the intervention on these behaviors was evaluated by multilevel regression analyses . All analyses were adjusted for baseline values and gender . Significance level was p≤0.01 . No significant intervention effects were observed , neither for self-reported TV/DVD or computer/game console time , nor for accelerometer-assessed total sedentary time and number of breaks in sitting time . The intervention group , however , reported more positive attitudes towards ( β = 0.25 ( 95 % CI 0.11 , 0.38 ) ) and preferences/liking for ( β = 0.20 ( 95 % CI 0.08 , 0.32 ) ) breaking up sitting time than the control group . Conclusions / Significance No significant intervention effect on self-reported screen time or accelerometer-assessed sedentary time or breaks in sitting time was observed , but positive effects on beliefs regarding breaking up sitting time were found in favor of the intervention group . Overall , these results do not warrant wider dissemination of the present UP4FUN intervention . Trial Registration International St and ard R and omized Controlled Trial Number Registry IS RCT We investigated the cross-sectional and prospect i ve associations between different sedentary behaviors and cognitive function in a large sample of adults with data stored in the UK Biobank . Baseline data were available for 502,643 participants ( 2006 - 2010 , United Kingdom ) . Cognitive tests included  prospect  i  ve memory  ( baseline only : n = 171,585 ) , visual-spatial memory ( round 1 : n = 483,832 ; round 2 : n = 482,762 ) , fluid intelligence ( n = 165,492 ) , and short-term numeric memory ( n = 50,370 ) . After a mean period of 5.3 years , participants ( numbering from 12,091 to 114,373 , depending on the test ) also provided follow-up cognitive data . Sedentary behaviors ( television viewing , driving , and nonoccupational computer-use time ) were measured at baseline . At baseline , both television viewing and driving time were inversely associated with cognitive function across all outcomes ( e.g. , for each additional hour spent watching television , the total number of correct answers in the fluid intelligence test was 0.15 ( 99 % confidence interval : 0.14 , 0.16 ) lower . Computer-use time was positively associated with cognitive function across all outcomes . Both television viewing and driving time at baseline were positively associated with the odds of having cognitive decline at follow-up across most outcomes . Conversely , computer-use time at baseline was inversely associated with the odds of having cognitive decline at follow-up across most outcomes . This study supports health policies design ed to reduce television viewing and driving in adults The aim of this study is to examine  sedentary and light activity  in relation to overweight in adolescent girls . Adolescent girls were r and omly recruited from 36 schools participating in the Trial of Activity for Adolescent Girls ( TAAG ) . Assessment s included age , ethnicity , socioeconomic status , and body composition estimated from weight , height , and triceps skinfold .  Sedentary and light activity  was measured for 6 days using accelerometry in 6th and in 8th grade among two r and omly sample d cross-sections of girls .  Sedentary activity  increased from the 6th to 8th grade by 51.5 min/day . In the 8th grade , a significantly higher number of hours in sedentary activity for each of the 6-days of measurement were evident with higher tertiles of percent body fat ( 30 - 35 % , > 35 % fat ) ( P < 0.05 ) , but not across all increasing tertiles of BMI ( 5th to 85th , 85th to 95th , and > 95th percentiles ) . The increase in sedentary activity was observed on weekdays , but not on weekends for percent body fat tertiles . In the cohort of girls measured in both 6th and 8th grade s , the mean cross-sectional coefficient estimates were significant for percent body fat , but not BMI for sedentary and light activities . Adolescent girls from the 6th to 8th grade are shifting their time from light to more  sedentary activity as measured by accelerometers . In addition , the increase in sedentary activity is not associated with an adverse effect on BMI or percent body fat . The eventual impact of this shift to a more sedentary lifestyle on body composition and other outcomes needs to be evaluated further Background : A number of cross‐sectional studies have suggested that higher levels of  sedentary behavior ( SB ) are associated with worse cognitive abilities  in older age . There is a paucity of longitudinal studies investigating this relationship utilizing objective ly assessed SB . This study investigated the relationship between objective ly assessed SB and future cognitive abilities in a cohort of older adults . Methods : A longitudinal study over 22.12 ± 1.46 months including 285 community‐dwelling older adults across 14 regions in Taiwan was undertaken . Cognitive ability was ascertained using a Chinese version of the Ascertain Dementia 8‐item Question naire ( AD8 ) and SB captured by 7 days accelerometer data . Multivariable negative binomial regression models adjusted for confounders were undertaken . Results : 274 community‐dwelling older adults finished the study ( age = 74.6 ± 6.2 , % female = 54.4 % ) . At baseline , 20.1 % ( n = 55 ) , 48.5 % ( n = 133 ) and 31.4 % ( n = 86 ) of the sample engaged in high ( 11 + h ) , medium ( 7–10.99 h ) and low ( < 7 h ) of SB respectively . In the fully adjusted model , higher levels of SB were associated with an increased risk of worse cognitive ability at follow up ( adjusted rate ratio (ARR)1.09 ( 95%CI:1.00–1.19 ) ) , with the strongest relationship evident in those engaging in over 11 h of SB ( ARR 2.27 ( 95%CI:1.24–4.16 ) ) . The relationship remained evident after adjusting for depressive symptoms and physical activity . Conclusion : Our data suggests that objective ly assessed SB , particularly when over 11 h a day , is independently associated with worse cognitive ability over a two year period . Our data adds to the pressing reasons to reduced SB in older age . HighlightsFirst prospect i ve study to investigate objective  ly sedentary behavior ( SB ) and cognition in older adults . Higher levels of objective SB were independently associated with worse cognitive ability over two years . This relationship was most pronounced in older people spending over 11 h a day being sedentary Background There is currently no vali date d question naire available to assess total sedentary time  in older adults . Most studies only used TV viewing time as an indicator of sedentary time . The first aim of our study was to investigate the self-reported time spent by older persons on a set of sedentary activities , and to compare this with objective sedentary time measured by accelerometry . The second aim was to determine what set of self-reported sedentary activities should be used to validly rank people ’s total sedentary time . Finally we tested the reliability of our newly developed question naire using the best performing set of sedentary activities . Methods The study sample included 83 men and women aged 65–92 y , a r and om sample of Longitudinal Aging Study Amsterdam participants , who completed a question naire including ten sedentary activities and wore an Actigraph GT3X accelerometer for 8 days . Spearman correlation coefficients were calculated to examine the association between self-reported time and objective sedentary time . The test-retest reliability was calculated using the intraclass correlation coefficient ( ICC ) . Results Mean total self-reported sedentary time was 10.4 ( SD 3.5 ) h/d and was not significantly different from mean total objective sedentary time ( 10.2 ( 1.2 ) h/d , p = 0.63 ) . Total self-reported sedentary time on an average day ( sum of ten activities ) correlated moderately ( Spearman ’s r = 0.35 , p < 0.01 ) with total objective sedentary time . The correlation improved when using the sum of six activities ( r = 0.46 , p < 0.01 ) , and was much higher than when using TV watching only ( r = 0.22 , p = 0.05 ) . The test-retest reliability of the sum of six sedentary activities was 0.71 ( 95 % CI 0.57 - 0.81 ) . Conclusions A question naire including six sedentary activities was moderately associated with accelerometry-derived sedentary time and can be used to reliably rank sedentary time in older persons Background Prospect i ve studies report associations between indicators of time spent sitting and  obesity risk .  Most studies use a single indicator of sedentary behavior and are unable to clearly identify whether sedentary behavior is a cause or a consequence of obesity . Purpose To investigate cross-sectional and prospect i ve associations between multiple sitting time indicators and  obesity  and examine the possibility of reverse causality . Methods Using data from the Whitehall II cohort , multiple logistic models were fitted to examine associations between prevalent obesity ( BMI ≥30 ) at Phase 5 ( 1997–1999 ) , and incident obesity between Phases 5 and 7 ( 2003–2004 ) across four levels of five sitting exposures ( work sitting , TV viewing , non-TV leisure-time sitting , leisure-time sitting , and total sitting ) . Using obesity data from three prior phases ( 1985–1988 , 1991–1993 ; and recalled weight at age 25 years ) , linear regression models were fitted to examine the association between prior obesity and sitting time at Phase 5 . Analyses were conducted in 2012 . Results None of the sitting exposures were associated with obesity either cross-sectionally or prospect ively . Obesity at one previous measurement phase was associated with a 2.43-hour/week ( 95 % CI=0.07 , 4.78 ) increase in TV viewing ; obesity at three previous phases was associated with a 7.42-hour/week ( 95 % CI=2.7 , 12.46 ) increase in TV-viewing hours/week at Phase 5 . Conclusions Sitting time was not associated with obesity cross-sectionally or prospect ively . Prior obesity was prospect ively associated with time spent watching TV per week but not other types of sitting Even when adults meet physical activity guidelines , sitting for prolonged periods can compromise metabolic health .  Television ( TV ) time and objective measurement studies show deleterious associations , and breaking up sedentary time is beneficial .  Sitting time , TV time , and time sitting in automobiles increase premature mortality risk . Further evidence from prospect i ve studies , intervention trials , and population -based behavioral studies is required Objective To examine whether physical activity ( PA ) and sedentary time ( ST ) in primary school-aged children are associated with adiposity at the start of secondary school , and whether these associations differ by sex or ethnic group . Design Nationally representative prospect i ve cohort study . Setting Children born across the UK , between 2000 and 2002 . Participants 6497 singleton children . Outcome measures Measures of adiposity ( body mass index ( BMI ) , fat mass index ( FMI ) and fat free mass index (FFMI))—obtained at 7 and 11 years . Explanatory measures  Total daily PA ( mean counts per minute ( cpm ) ) ; minutes of moderate-to-vigorous PA ( MVPA ) ; and ST .  All assessed at 7 years using accelerometers . Results In cross-sectional analyses , total PA was inversely associated with FMI ( 3.7 % ( 95 % CI 2.7 % to 4.7 % ) reduction per 150 cpm increase ) , as was MVPA ( 4.2 % ( CI 3.2 % to 5.2 % ) reduction per 20 min/day increase ) . Associations were stronger in black and South Asian ethnic groups . Total PA and MVPA were not associated with FFMI . ST was positively associated with FMI ( 1.3 % ( CI 0.2 % to 2.3 % ) increase per 50 min/day increase ) and inversely associated with FFMI ( 0.5 % ( CI 0.2 % to 0.7 % ) reduction per 50 min/day increase ) . Longitudinally , MVPA at age 7 years remained inversely associated with FMI at age 11 years ( 1.5 % ( CI 0.4 % to 2.6 % ) reduction per 20 min/day increase ) . No association was found between total PA and ST and any of the later adiposity measures . Conclusions 7-year-old children who are more physically active are less likely to be obese at that age and at age 11 years . These associations were particularly evident in children from black or South Asian ethnicity at age 7 years and in boys at age 11 years . Measurements of fat mass provide valuable insights into ethnic differences in associations between adiposity and activity
There was consistent evidence from cross-sectional data of an unfavourable association between total sedentary time and insulin sensitivity .
There was also some evidence that total sedentary time was unfavourably associated with fasting insulin , insulin resistance and triglycerides .
Furthermore , there was some evidence from cross-sectional data of a favourable association between breaks in sedentary time and triglycerides .
CONCLUSION Total sedentary time was consistently shown to be associated with poorer insulin sensitivity , even after adjusting for time spent in physical activity .
OBJECTIVE We conducted a systematic review to investigate the cross-sectional and prospect i ve associations of accelerometer-measured total sedentary time and breaks in sedentary time with individual cardiometabolic biomarkers in adults ≥18years of age .