Improved arterial flow-mediated dilation after exertion involves hydrogen peroxide in overweight and obese adults following aerobic exercise training

Abstract

Objective: Acute strenuous physical exertion impairs arterial function in sedentary adults. We investigated the effects of 8 weeks of regular aerobic exercise training on acute physical exertion-induced arterial dysfunction in sedentary, overweight, and obese adults. Methods: Twenty-five overweight and obese adults (BMI 30.5±7.2 years) were assigned to 8 weeks of aerobic training or to a control group. Brachial artery flow-mediated dilation (FMD) was assessed before and after acute leg press exercise at weeks 0 and 8. Gluteal adipose biopsies were performed at rest and post acute leg press to measure microvessel FMD with and without nitric oxide synthase inhibition via l NG -nitroarginine methyl ester or hydrogen peroxide (H 2 O 2) scavenging with Catalase. Microvessel nitric oxide and H 2 O 2 production were assessed via fluorescence microscopy. Results: Brachial artery dilation was reduced post acute leg press at week 0 in the aerobic exercise and control groups, but was preserved in the aerobic-exercise group post acute leg press at week 8 (P<0.05). Post acute leg press microvessel FMD was preserved in the aerobic exercise group but impaired in the control group at week 8 (P<0.05). Preserved dilation in the aerobic exercise group was more sensitive to H 2 O 2 scavenging than inhibition of nitric oxide, and post acute leg press microvessel H 2 O 2 production was increased compared with at rest (P<0.05). Conclusion: Aerobic exercise prevents acute exertion-induced arterial dysfunction in overweight and obese adults via a phenotypic switch from nitric oxide-mediated dilation at rest to a predominately H 2 O 2 -mediated dilation after acute physical exertion.