[Effect of moderate exercise for 30 min at 30 min versus 60 min after dinner on glycemic control in patients with type 2 diabetes: a randomized, crossover, self-controlled study]

Abstract

Objective: To compare the effectiveness of moderate exercise for 30 min at 30 min and 60 min after dinner on glycemic control in patients with type 2 diabetes.

Methods: This randomized, crossover, self-controlled pilot study was conducted in 15 inactive patients with type 2 diabetes without serious complications or use of exogenous insulin. The participants completed two randomly ordered exercise protocols (brisk walking for 30 min at 30 min or 60 min after dinner on the exercise day) spaced 1 week apart. All the exercise was performed while maintaining a heart rate reserve of 40%. The interstitial glucose level was monitored using a continuous glucose monitor (CGM) for all the participants, who maintained a standardized diet with routine medications. The 2-h postprandial mean glucose, peak glucose, and glucose area under the curve (AUC) were measured. The mean amplitude of glycemic excursions (MAGE) and other plasma glucose fluctuation parameters in 12 h after dinner, including the mean blood glucose (MBG) and the coefficient variation (CV) of glucose, were also calculated. The incidence of nocturnal hypoglycemia was recorded in all the participants.

Results: The participants had a mean age of 46±11 years with a mean BMI of 25.8±3.1 kg/m² and a mean HbA1c of 7.7%. No significant differences were found between postprandial 30 min exercise group and postprandial 60 min exercise group in terms of 2-h postprandial mean glucose, peak glucose, glucose AUC, or in MBG, CV and MAGE during the 12-h period after dinner. No nocturnal hypoglycemia occurred in the participants after exercise at 30 or 60 min after dinner. However, significant reductions in the 2-h postprandial glucose levels were detected after exercise at 60 min after dinner as compared to exercise at 30 min.

Conclusions: The timing (30 min vs 60 min after dinner) of moderate exercises for 30 min does not produce significant difference in the improvement of postprandial hyperglycemia in type 2 diabetic patients, and both exercise protocols are safe without a potential risk of hypoglycemia. Nevertheless, exercise at 60 min after dinner can be more effective to lower 2-h postprandial glucose, while exercise at 30 min after dinner might be safer for patients with a high risk of hypoglycemia.

Keywords: diabetes mellitus, type 2; exercise; hyperglycemia; postprandial period.

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晚餐后0.5 h运动组与晚餐后1 h运动组CGM血糖平均值及与餐前血糖差值曲线图 Average CGM values and average postprandial CGM glucose change from baseline in postprandial 0.5 h exercise and postprandial 1 h exercise groups during the postprandial period. Time 0 represents the time of first bite. ^*P < 0.05 between the two conditions.