Break It Up: A Study Evaluating Breaking Up Daily Sedentary Behavior in Youth

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)