Effect of a single vs multiple bouts of exercise on glucose control in women with type 2 diabetes.

The Surgeon General and Centers for Disease Control and Prevention have recommended that multiple bouts of exercise can be accumulated throughout the day in lieu of the more traditional single, longer bout of exercise. Yet, conclusive evidence does not exist suggesting these 2 training modes provide similar health-related benefits on metabolic control, especially in individuals with type 2 diabetes. The purpose of this study was to determine if differences exist in glucose control when preceded by one 30-minute or three 10-minute bouts of exercise in women with type 2 diabetes. Nine individuals with type 2 diabetes (53 +/- 6 years old) and 6 control women (49 +/- 4 years old) completed 3 randomly ordered oral glucose tolerance tests (OGTTs). Two of the OGTTs were preceded the day prior by moderate exercise (approximately 60% of Vo2peak), either one 30-minute or three 10-minute bouts, whereas the third OGTT was used as a control day with no exercise performed 3 days prior. Glucose and insulin were measured every 30 minutes for 4 hours during the OGTT. Individuals with type 2 diabetes exhibited a greater overall glucose response than the controls (P < .05), but the glucose response to the OGTT was not different between the 3 conditions within each group (2-hour glucose: multiple bout, 14.3 +/- 3.2 vs 5.0 +/- 1.7; single bout, 14.1 +/- 3.0 vs 4.7 +/- 1.5; control day, 14.6 +/- 2.7 vs 4.9 +/- 4.9 mmol/L). Glucose area under the curve analysis resulted in similar findings. As expected, the group with type 2 diabetes had greater fasting insulin levels compared with the control group for all exercise conditions (multiple bout: 4.5 +/- 1.2 vs 0.3 +/- 0.2; single bout: 6.4 +/- 1.6 vs 0.9 +/- 0.4; control day: 5.7 +/- 1.8 vs 1.5 +/- 0.6 pmol/L; P < .05). Exercise or no exercise did not alter the insulin response to the OGTT for either group. Despite a higher glucose response to the glucose load in T2D, an acute exercise bout (single or multiple bouts) did not appear to alter glucose control the following day in either the individuals with type 2 diabetes or the control group.