Exercise and 24-h Glycemic Control: Equal Effects for All Type 2 Diabetic Patients?
van Dijk, Jan-Willem × Manders, Ralph Canfora, Emanuel E van Mechelen, Willem Hartgens, Fred Stehouwer, Coen D A van Loon, Luc J C #
American College of Sports Medicine
Medicine and Science in Sports and Exercise vol:45 issue:4 pages:628-635
PURPOSE: We assessed the impact of a single bout of moderate-intensity exercise on subsequent 24 h glycemic control in 60 type 2 diabetic patients. Moreover, we examined whether individual responses to exercise were related to subjects' baseline characteristics, including age, BMI, diabetes duration, exercise performance, medication, and HbA1c content. METHODS: Sixty type 2 diabetic patients (insulin-treated n=23) participated in a randomized crossover experiment. Patients were studied on 2 occasions for 3 days under strict dietary standardization, but otherwise free-living conditions. Parameters of glycemic control (means [95%CI]) were assessed by continuous glucose monitoring over the 24 h period following a single bout of moderate-intensity endurance-type exercise or no exercise at all (control). RESULTS: Type 2 diabetic patients experienced hyperglycemia (blood glucose >10 mmol/L) for as much as 8:16 h:min (6:44 to 9:48) per day. The prevalence of hyperglycemia was reduced by 31% to 5:38 h:min (3:17 to 7:00) over the 24 h period following the exercise bout (P<0.001). Moreover, exercise lowered average blood glucose concentrations by 0.9 mmol/L (0.7 to 1.2) and reduced glycemic variability (P<0.05). The response to exercise showed considerable variation between subjects, and correlated positively with HbA1c levels (r=0.38, p<0.01). Nevertheless, even well-controlled patients with an HbA1c level below 7.0% (n=28) achieved a 28% reduction in the daily prevalence hyperglycemia following exercise (P<0.01). CONCLUSIONS: A single bout of moderate-intensity exercise substantially improves glycemic control throughout the subsequent day in insulin- and non-insulin treated type 2 diabetic patients. Of all baseline characteristics, only subjects' HbA1c level is related to the magnitude of response to exercise. Nevertheless, the present study demonstrates that even well-controlled patients benefit considerably from the blood glucose-lowering properties of daily exercise.