RESUMO
INTRODUCTION: Glycemic instability is a severely underestimated problem in type 2 diabetes treatment. Therapeutic targets should aim to reduce postprandial blood glucose excursions. Exercise prescription can effectively improve glucose homeostasis and reduce the risk of cardiovascular complications. AIM: To assess the impact of a single, isoenergetic bout of low- (LI) and high-intensity (HI) exercise on the prevalence of hyperglycemia throughout the subsequent 24-h postexercise period in longstanding type 2 diabetes patients. METHODS: Nine sedentary, male type 2 diabetes patients (age = 57 +/- 2 yr, body mass index = 29.0 +/- 1.0 kg x m(-2), Wmax = 2.2 +/- 0.2 W x kg(-1) body weight) were selected to participate in a randomized crossover study. Subjects performed an isoenergetic bout of endurance-type exercise for 60 min at 35% Wmax (LI) or 30 min at 70% Wmax (HI) or no exercise at all (NE). Thereafter, glycemic control was assessed during the subsequent 24-h postexercise period by continuous glucose monitoring under strict dietary standardization but otherwise free-living conditions. RESULTS: Average 24-h glucose concentrations were reduced after the LI exercise bout (7.8 +/- 0.9 mmol x L(-1)) when compared with the control experiment (9.4 +/- 0.8 mmol x L(-1); P < 0.05). The HI exercise bout did not significantly lower mean glucose concentrations (8.7 +/- 0.7 mmol x L(-1); P = 0.14). Hyperglycemia was prevalent for as much as 35% +/- 9% throughout the day (NE). A single bout of exercise reduced the prevalence of hyperglycemia by 50% +/- 4% (P < 0.05) and 19% +/- 9% (P = 0.13) in the LI and HI exercise experiments, respectively. CONCLUSIONS: A single bout of LI, as opposed to HI, exercise substantially reduces the prevalence of hyperglycemia throughout the subsequent 24-h postexercise period in longstanding type 2 diabetes patients.