The Impact of Obesity on Endothelial Function Following Acute Maximal Aerobic Exercise

Obesity prevalence has rapidly increased in the United States to over 40%. The low-grade chronic inflammation with obesity is linked to increased risk of cardiovascular disease. Impairment of endothelium-dependent vasodilation is one of the first subclinical stages in the atherosclerotic process. Although some information exists on the effects of exercise training on endothelial function, there is limited data on the acute effects of maximal exercise on endothelial function in obese individuals. Study Objective: This study aimed to investigate the effects of maximal aerobic exercise on endothelial function, specifically serum C1q-TNF-related-protein-9 (CTRP9), serum total nitric oxide (NOx), and brachial artery flow-mediated dilation (FMD) in obese and normal-weight individuals. Hypothesis: We hypothesized that increased serum CTRP9 following maximal aerobic exercise would be observed in both obese and normal-weight participants; however, only the normal-weight participants would have increased FMD and serum NOx in response to exercise. Methods: Sixteen young male participants (9 obese and 7 normal-weight) participated in a maximal graded exercise test on a treadmill. CTRP9, NOx, and FMD measurements were taken prior to, immediately following exercise, and 1 hour and 2 hours into recovery. Statistical analyses included repeated measures ANOVA and Pearson correlations. Results: There was a significant time effect for serum CTRP9 following maximal exercise (p=0.049) with a significant decrease in serum CTRP9 in both groups from immediately after exercise to 1 hour after exercise (p=0.007). There was also a significant time effect for serum NOx following exercise (p=0.04) with a significant increase in serum NOx levels in both groups from baseline to immediately after exercise (p=0.018) that returned to baseline during recovery. FMD did not significantly change across time (p=0.452), although obese participants had lower FMD vs. normal-weight participants (p=0.017). Additionally, CTRP9 was positively correlated with NOx across all timepoints (r=0.273, p=0.029). Conclusions: Maximal intensity exercise significantly elevates NOx, transiently decreases CTRP9 and does not alter FMD with similar responses between obese and normal-weight participants. The results from this study provide a foundation for additional examination of the acute impacts of maximal intensity exercise on endothelial function in individuals with obesity. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.