Effects of resistance exercise bouts of different intensities but equal work on EPOC

THORNTON, M. K., and J. A. POTTEIGER. Effects of resistance exercise bouts of different intensities but equal work on EPOC. Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 715–722, 2002. Purpose To compare the effect of low- and high-intensity resistance exercise of equal work output, on exercise and excess postexercise oxygen consumption (EPOC). Methods Fourteen female subjects performed a no-exercise baseline control (CN), and nine exercises for two sets of 15 repetitions at 45% of their 8-RM during one session (LO) and two sets of 8 repetitions at 85% of their 8-RM during another session (HI). Measures for all three sessions included: heart rate (HR) and blood lactate (La) preexercise, immediately postexercise and 20 min, 60 min, and 120 min postexercise; and ventilation volume (V̇E), oxygen consumption (V̇O2), and respiratory exchange ratio (RER) during exercise and at intervals 0–20 min, 45–60 min, and 105–120 min postexercise. Results Exercise V̇O2 was not significantly different between HI and LO, but V̇E, [La], and HR were significantly greater for HI compared with LO. Exercise RER for HI (1.07 ± 0.03 and LO (1.05 ± 0.02) were significantly higher than CN (0.86 ± 0.02), but there were no differences among conditions postexercise. EPOC was greater for HI compared with low at 0–20 min (HI,1.72 ± 0.70 LO2; LO, 0.9 ± 0.65, LO2), 45–60 min (HI, 0.35 ± 0.25 LO2; LO, 0.14 ± 0.19 LO2), and 105–120 min (HI, 0.22 ± 0.22 LO2; LO, 0.05 ± 0.11, LO2). Conclusion These data indicate that for resistance exercise bouts with an equated work volume, high-intensity exercise (85% 8-RM) will produce similar exercise oxygen consumption, with a greater EPOC magnitude and volume than low-intensity exercise (45% 8-RM).