Effects of Exercise Intensity on Postexercise Endothelial Function and Oxidative Stress

Purpose. To measure endothelial function and oxidative stress immediately, 90 minutes, and three hours after exercise of varying intensities. Methods. Sixteen apparently healthy men completed three exercise bouts of treadmill running for 30 minutes at 55% VȮ 2max (mild); 20 minutes at 75% VȮ 2max (moderate); or 5 minutes at 100% VȮ 2max (maximal) in random order. Brachial artery flow-mediated dilation (FMD) was assessed with venous blood samples drawn for measurement of endothelin-1 (ET-1), lipid hydroperoxides (LOOHs), and lipid soluble antioxidants. Results. LOOH increased immediately following moderate exercise (푃 < 0.05). ET-1 was higher immediately after exercise and 3 hours after exercise in the mild trial compared to maximal one (푃 < 0.05). Transient decreases were detected for ΔFMD/ShearAUC from baseline following maximal exercise, but it normalised at 3 hours after exercise (푃 < 0.05). Shear rate was higher immediately after exercise in the maximal trial compared to mild exercise (푃 < 0.05). No changes in baseline diameter, peak diameter, absolute change in diameter, or FMD were observed following any of the exercise trials (푃 > 0.05). Conclusions. Acute exercise at different intensities elicits varied effects on oxidative stress, shear rate, and ET-1 that do not appear to mediate changes in endothelial function measured by FMD.