Impact of β-blocker treatment and nutritional status on glycemic response during exercise in patients with type 2 diabetes

Abstract

Purpose: Most individuals with type 2 diabetes are affected by hypertension and thus have higher risk of cardiac complications. In addition to behavioural modifications, such as healthy food choices and regular physical activity, β-blocker treatment may be considered to reduce morbidity and mortality, especially after a cardiovascular event. However, this medication is generally associated with a deleterious impact on glucose metabolism. The objective of the study was to assess the impact of β-blocker treatment on glucose response during exercise in patients with type 2 diabetes, free of cardiovascular complications. Methods: Ten sedentary men, treated with diet and/or hypoglycemic agents have performed four exercise sessions at 60% of their V̇ O 2peak, in the fasted state or 2 hours following a standardized breakfast, with and without β-blockers (atenolol 100 mg id for five consecutive days). Blood samples were drawn during the resting period, at 15-min intervals during the exercise session and during the recovery period. Results: A reduction of blood glucose levels was observed following the exercise session in the postprandial state (48% and 44% reduction with and without β-blockers respectively; P<0.001). One hour of exercise performed in the fasted state had a minimal impact on glucose and insulin levels, whether with or without β-blockers. β-blocker treatment was not associated with increased baseline blood glucose or insulin levels in the fasted or the postprandial situation. Conclusion: Dietary status has a more important impact on plasma glucose and insulin modulation than short-term use of β-blockers. © 2007 CIM.