Cardiorespiratory fitness level correlates inversely with excess post-exercise oxygen consumption after aerobic-type interval training

BACKGROUND: The purpose of this study was to reveal any association between cardiorespiratory fitness level and excess post-exercise oxygen consumption (EPOC) using three cycling protocols with varying degrees of exercise intensity, i.e., sprint interval training (SIT), high-intensity interval aerobic training (HIAT), and continuous aerobic training (CAT). FINDINGS: Ten healthy men, aged 20 to 31 years, attended a cross-over experiment and completed three exercise sessions: SIT consisting of 7 sets of 30-s cycling at 120% VO(2max) with a 15-s rest between sets; HIAT consisting of 3 sets of 3-min cycling at 80~90% VO(2max) with a 2-min active rest at 50% VO(2max) between sets; and CAT consisting of 40 min of cycling at 60~65% VO(2max). During each session, resting VO(2), exercise VO(2), and a 180-min post-exercise VO(2) were measured. The net exercise VO(2) during the SIT, HIAT, and CAT averaged 14.7 ± 1.5, 31.8 ± 4.1, and 71.1 ± 10.0 L, and the EPOCs averaged 6.8 ± 4.0, 4.5 ± 3.3, and 2.9 ± 2.8 L, respectively. The EPOC with SIT was greater than with CAT (P < 0.01) and HIAT (P = 0.12). Correlation coefficients obtained between subjects’ VO(2max) and the ratio of EPOC to net exercise VO(2) for SIT, HIAT, and CAT were −0.61 (P = 0.06), -0.79 (P < 0.01), and −0.42 (P = 0.23), respectively. CONCLUSIONS: Our data suggest that cardiorespiratory fitness level correlates negatively with the magnitude of EPOC, especially when performing aerobic-type interval training.