break it up: a study evaluating breaking up daily sedentary behavior in youth

Conditions: Healthy; Obesity; Overweight

Summary: background: some studies have found that people can better process sugars when they take walking breaks. studies have also found that children's attention and memory may improve after exercise. it is not known if short walking breaks have the same effects. researchers want to study if breaking up sitting with walking for 6 days helps children s bodies use sugars and improves concentration. objectives: to learn if breaking up sedentary (low-activity) time with short walking breaks over 6 days affects how children s bodies use sugar. to learn if breaking up sedentary time changes children s attention, memory, feelings, activity, or eating. eligibility: children ages 7-11 in general good health design: participants will be screened with: * medical history * physical exam * fasting blood tests. on 2 out of 7 total study visits, participants cannot eat or drink after 10 p.m. the night before. * full-body x-ray * ekg (electronic signals that record heart function through stickers) * treadmill exercise. heart, blood pressure, and oxygen will be monitored. * questions about the child s health, socialization, and activity, and parent s education and economic status * picture vocabulary test * dietician meeting (questions about eating habits) participants will have visits on 6 consecutive days. over that time, they will wear 2 devices to monitor blood sugar and activity (even while at home). participants will have 5 after-school visits. these include: * health check * snack plus food for the next 24 hours * activity monitored * 3-hour sitting tests. participants will do non-active things. some will have 3-minute walks every 30 minutes. * cognitive tests and questions about mood and anxiety are given on days #1 \& 5. participants will fast before the last visit in the morning. they will have: * 9 blood draws by iv catheter. participants will drink sugar water. * sitting test * activity monitored * meal (food buffet)

background: sedentary behavior is defined as a set of low-intensity activities involving limited body movement (e.g.: tv viewing, prolonged sitting). some studies have found higher levels of childhood sedentary behavior predict higher body mass index (bmi) and metabolic abnormalities. we and others have found that interrupting sitting with short, 2-3 minute bouts of moderate activity (walking) can improve glucose tolerance during a single session. thus, interrupting sedentary behavior may be an intervention strategy to reduce health risks. objective: we propose to conduct a randomized pilot study to assess whether interrupting sedentary behavior for 6 consecutive days provides sustained improvement in carbohydrate metabolism without negatively impacting executive function, attention, mood, anxiety, dietary intake or usual physical activity. design \& population: using a randomized parallel group design, children, ages 7-11 years, will complete an assigned randomized condition of either 6 consecutive days of 3 hours of monitored sedentary activity (sitting) or 6 consecutive days of 3 hours of interrupted sitting (in which they will be prompted to walk for 3 minutes every 30 minutes). outcome measures: twenty-four-hour continuous glucose monitoring and postprandial insulin incremental area under the curve (iauc) on post-condition oral glucose tolerance testing will be the primary measures. secondary measures include: postprandial glucose iauc, executive function, attention, mood, anxiety, dietary intake, and free-living physical activity. impact: this project will investigate if consecutive daily interruption of sitting behaviors improves glucose tolerance, a potential negative health consequences of sedentary behavior in children. if repeatedly interrupting sitting with short bouts has sustained beneficial effects among children, interventions examining the frequency, duration, and intensity of such interruptions could be developed for use in the community setting. thus, these results have the potential to provide insight into novel behavioral intervention targets in youth.

Eligibility criteria:
* inclusion criteria: participants will qualify for the study if they meet the following criteria: 1. good general health. 2. age greater than or equal to 7 and less than 12 years. 3. fasting plasma glucose less than 100 mg/dl 4. body mass index (bmi) greater than or equal to the 5th percentile, as determined by the cdc age- and sex- specific growth charts. exclusion criteria: participants will be excluded from the study for: 1. significant cardiac or pulmonary disease likely to or resulting in hypoxia or decreased perfusion. 2. evidence of impaired glucose tolerance or type 2 diabetes, including fasting plasma glucose greater than or equal to 100 mg/dl. 3. presence of other endocrinologic disorders leading to obesity (e.g.: cushing syndrome). 4. participants who have, or whose parent/guardians have, current substance abuse or a psychiatric disorder or other condition that, in the opinion of the investigators, would impede competence, compliance, or prevent the completion of the study. 5. participants who have, or are currently receiving, anti-psychotic drugs that would affect metabolism, cognitive outcomes, and body habitus. 6. participants receiving medical treatment other than diet for hypertension or dyslipidemia. 7. participants with precocious puberty and/or receiving androgen and estrogen therapy. 8. participants currently taking medications for adhd, or any disorder or use of medications known to affect body composition or weight including but not limited to glucocorticoids or other steroid compounds. 9. presence of pre-existing neurocognitive disabilities, or an age-adjusted score below 85 on the picture vocabulary test at the screening visit. 10. presence of food allergies, such as peanut/tree nut, dairy, soy or any other food allergy or personal dietary restrictions that would preclude participant from consuming the daily diet or the buffet. 11. presence of significant skin disease or allergy to adhesive material prohibiting placement of a continuous glucose monitor. 12. participants unable or unwilling to abstain from acetaminophen, ascorbic acid, or salicylic acid during study duration. 13. participant does not speak fluent english. 14. participant is or becomes pregnant. 15. participant has an ambulatory impairment optional mrs supplemental arm inclusion criteria (a) participants will qualify for the study if they qualify for the primary break it up! study. exclusion criteria 1. cannot have mri scanning. some of the reasons a child might not be able to have mri include: * implanted cardiac pacemaker or defibrillator * cochlear implants * ocular foreign body (e.g. metal shavings) * embedded shrapnel fragments * central nervous system aneurysm clips * implanted neural stimulator * medical infusion pumps * any implanted device that is incompatible with mri. 2. is not likely to tolerate an mri scan. examples of medical conditions that would make it difficult to undergo mri include severe anxiety (nervousness) or hyperactivity which make it hard for your child to lay flat for the study. 3. requires sedation for mri studies. 4. has a condition that makes entry into the scanner difficult (e.g. weight over 550 lbs, claustrophobia, etc.). 5. has severe back-pain or motion disorders that make it hard for a child to lie on his/her back within the mri scanner and hold still for the scan.

Keywords: metabolism children walking bouts glucose insulin