Effects of Interrupting Sedentary Time on Glycemic Control in Older Overweight and Obese Adults

Increasing physical activity in older adults has important implications for treating obesity related metabolic conditions, however the interaction of aging- and obesity-related declines in physical function may make adding structured exercise particularly challenging for this group. Given these challenges, an alternative prescription to traditional structured exercise, may be short bouts of intermittent walking scattered throughout the day - this may be an effective strategy to increase physical activity, reduce sedentary behavior, and improve glycemic control in overweight/obese older adults. The purpose of this project is to determine how interrupting sedentary time with short bouts of moderate intensity walking affects important metabolic outcomes in older, overweight adults. It would also be of interest to compare the effects of short, frequent interruptions in sedentary behavior to a traditional exercise prescription (continuous 30 min walking bout) on metabolic outcomes (e.g., glycemic control, insulin sensitivity, and 24 h fat oxidation). Thus, the overall aims of the proposed research are to 1) Determine the effect of performing short bouts of moderate-intensity intermittent walking (IW) on glucose and insulin metabolism compared to uninterrupted sitting (US) in older overweight and obese adults. 2) To compare the effects of interrupting sedentary time (IW) vs. a traditional exercise prescription (continuous 30 m walk (CW)) on metabolism. The investigators hypothesize that interrupting sedentary time with intermittent walking will improve glucose and insulin metabolism compared to uninterrupted sitting and it will be as effective at improving metabolism as a single continuous 30 min walk.