Smoking Counteracts the Favorable Effect of Exercise Training on Endothelial Function in Patients with Type 2 Diabetes

Background: Exercise training can improve endothelial function in patients with diabetes. We hypothesized that the favorable effect of exercise training on endothelial function in patients with diabetes is counteracted by cigarette smoking. Purpose: To assess whether there is a difference in the effect of exercise on endothelial function in smokers and non-smokers with type 2 diabetes. Methods: We performed a 3-month controlled trial in 27 never-smoking and 17 smoking individuals with type 2 diabetes who participated in a home-based walking program. The percentage decrease in post-exercise ankle-brachial pressure index (ABI), which is an index of endothelial function, was assessed at baseline and after 3 months. Results: Compared to the smoking group, the never-smoking group showed a more significant improvement in post exercise ABI during the 3 months of home-based training (interaction, P < 0.01). Conclusions: These results indicate that smoking may counteract the favorable effects of exercise training on endothelial function. Endothelial function plays an important role in the prevention of cardiovascular disease among patients with diabetes. Therefore, a Certified Diabetes Educator should strongly advise diabetic patients not to smoke.