Exercise and 24-h Glycemic Control: Equal Effects for All Type 2 Diabetes Patients?
Van Dijk,J.W., Manders,R.J., Canfora,E.E., et al (2013) Med.Sci.Sports Exerc. 45:628-635
Objective: To assess the effect of a single bout of moderate-intensity exercise on subsequent 24-h glycemic control in people with T2DM
Design: Randomized crossover design. Patients were studied on 2 occasions for 3-d under strict dietary standardization (all food provided) but otherwise free-living conditions. Glycemic control assessed for 24-hr after a single bout of moderate-intensity endurance-type exercise (40 - 60 min cycling at 35-50% maximal aerobic power) or no exercise (control).
Setting: Maastricht University Medical Centre. Patients were recruited as part of a larger project to elucidate the effects of different exercise modalities on glycemic control.
Participants: 60 men with type 2 diabetes (insulin treated (IDDM n=23) and non-insulin treated (NIDDM n=37). Exclusions included renal failure, liver disease, morbid obesity, uncontrolled hypertension, and history of severe cardiovascular disease.
Main outcome measures: Mean daily blood [glucose], prevalence of hyper- and hypoglycemia, glycemic variability. Blood [glucose] assessed with continuous glucose monitoring.
Results: At baseline the only differences between IDDM and NIDDM were longer duration of diagnosis and slightly higher HbA1c in IDDMs. Average 24-h blood [glucose] was 0.9 mmol/L lower after exercise and not different between the medication groups. There were large inter-individual differences in the response to exercise. The change in 24-h blood [glucose] only correlated with baseline HbA1c (r= 0.38, p<.01). The change in 24-h blood [glucose] was significantly greater in suboptimally controlled patients (i.e those with HbA1c >7%), although it was also significantly reduced in well-controlled patients. Prevalence of hyperglycemia (blood [glucose] > 10 mmol/L) from went from 8:16 to 5:38 (h:min). There was no effect on prevalence of hypoglycemia (blood [glucose] < 3.9 mmol/L). Glycemic variability was also reduced by exercise.
Conclusions: A single bout of moderate-intensity exercise improves glycemic control throughout the subsequent day in both IDDM and NIDDM. HbA1c was related to the magnitude of response. However, even well-controlled patients appear to benefit from the exercise.
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