Chia-Ling, L., Mikat, R. P., Udermann, B. E., & Skemp-Arlt, K. M. (2007). Effect of time of a day on EPOC magnitude and duration. ACSM Annual Meeting New Orleans, Presentation Number 754.

The purpose of this study was to examine the effect of time-of-day on Excess Post-Exercise Oxygen Consumption (EPOC) magnitude and duration following a 30-minute bout of moderate-intensity cycling. Moderately aerobically trained women (N = 16) performed three 30-minute bouts of exercise on a cycle ergometer at 65% of their age-predicted maximum heart rate. Bouts were separated by at least two days and were randomly ordered for early morning (05:00-07:00), mid-day (11:00-13:00), and early evening (17:00-19:00). Following each exercise bout, Ss rested while their post-exercise oxygen consumption rates were measured for 30 minutes.

There were no differences between mean durations of EPOC at any of the three times. EPOC magnitude increased significantly from morning to evening.

Implication. Post-exercise oxygen consumption is greater in the evening than in the morning. Aerobic performances are likely to be better later in the day.

Return to Table of Contents for this issue.