The Effects Of An “Exercise Snack” On Acute Glucose Response In Prediabetic And Diabetic Adults

Recent evidence suggests that a brief exercise bout is effective at improving glucose metabolism in healthy adults but there are limited data on the effects in individuals with insulin resistance. PURPOSE: To determine the effects of a brief bout of exercise (self -selected intensity) on the glucose response in individuals with prediabetes and type 2 diabetes. METHODS: Fifteen prediabetic (HbA1C: 5.9 ± 0.1; age: 43.3 ± 3.0 yrs) and 15 type 2 diabetic (HbA1C: 6.9 ± 0.2; age: 51.4 ± 1.8 yrs) males (n = 13) and females (n = 17) participated in this repeated measure crossover design. Following a baseline assessment, three experimental trials were performed on separate days, in random order: 1) sedentary control (CON); 2) 5-minute walking (WALK); and 3) 5-minute combined arm/leg cycling (BIKE). Each trial included a 60-minute oral glucose tolerance test (OGTT). RESULTS: Incremental area-under-the-curve (iAUC) was significantly lower following BIKE (400.9 ± 33.6 mg/dl/hr; p < 0.001) but not WALK (547.2 ± 42.3 mg/dl/hr; p = 0.13) compared to CON (586.8 ± 44 mg/dl/hr). Total area-under-the-curve (tAUC) was also significantly lower following BIKE (1420.6 ± 44.8 mg/dl/hr; p < 0.001) but not WALK (1560.5 ± 61.7 mg/dl/hr; p = 0.11) compared to CON (1598.7 ± 58.4 mg/dl/hr). In addition, both iAUC (p < 0.05) and tAUC (p < 0.05) were significantly lower for BIKE compared to WALK. There were no significant effects of diabetes status (pre vs. diabetic) or gender. In support of the findings that BIKE was more effective at lowering glucose response, the difference between CON and BIKE iAUC (iAUC CON - BIKE: 186.0 ± 34.7 mg/dl/hr;) and tAUC (tAUC CON - BIKE: 178.1 ± 39.0 mg/dl/hr;) was greater than the difference between CON and WALK, for both iAUC and tAUC, respectively (iAUC CON – WALK: 39.7 ± 32.3 mg/dl/hr; p < 0.05; tAUC CON – WALK: 38.2 ± 35.9 mg/dl/hr; p < 0.001). In addition, exercise VO2 was greater for BIKE (17.3 ± 0.7 mg/kg/min; p < 0.001) vs. WALK (13.8 ± 0.6 ml/kg/min). CONCLUSION: These results indicate that a brief bout of combined arm and leg cycling is effective at lowering the glucose response to an OGTT. The effectiveness of the exercise bout may be associated with exercise intensity. Importantly, this evidence suggests that chronic use of daily exercise snacks may improve glycemic control in prediabetics and type 2 diabetics. Supported by: Fundeded by Southern Illinois University Edwardsville Seed Grants for Transitional and Exploratory Projects