ABSTRACT

　Postprandial lipemia and reductions in endothelial function, as assessed by flow-mediated dilation （FMD）， are well-established responses to high-fat meal consumption. These responses are known to be attenuated by prior aerobic exercise. Emerging evidence suggests that low daily physical activity may blunt the beneficial effects of exercise on postprandial fat metabolism, yet the effects on FMD have not been examined. Therefore, this study aimed to investigate the influence of daily step count and aerobic exercise on FMD following high-fat meal consumption. Six healthy adults completed three, 5-day trials in a randomized crossover design, each with differing physical activity levels. After 2 days of controlled activity, subjects completed 2 days of either LOW（?5,000 steps/day） or ACTIVE（?10,000 steps/day） step counts. On the evening of day 4, subjects performed a 60-minute cycling bout. In a separate CONTROL trial, participants followed the LOW condition without exercise. High-fat meal tolerance tests were conducted the following morning, and postprandial responses were assessed over a 6-hour period. Serum triglyceride levels were, on average, 34% lower in the ACTIVE condition compared to CONTROL（p < 0.05）， but no significant differences were observed between LOW and the other conditions. Brachial artery FMD was decreased at 2- and 4-hours post-meal in the CONTROL condition （p < 0.05）．In addition, FMD was greater at 2 hours post-meal in the ACTIVE condition compared to CONTROL（p < 0.05）．These findings suggest that prior aerobic exercise may attenuate postprandial lipemia and reductions in FMD. However, low daily physical activity may limit the extent of these benefits. Further research with larger sample sizes is warranted to confirm these effects.

DECENTE SPORTS SCIENCE Vol.47/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE