Oxygen Consumption and Energy Expenditure of Different Intensities of Weight-Training in Women

Abstract

Few studies have examined the oxygen consumption and energy expenditure of weight training performed at different exercise intensities, but with similar exercise volumes, in women. PURPOSE: Therefore, the purpose of this study was to compare the total oxygen consumption (exercise + recovery between sets) and energy expenditure of multi-set, circuit weight training at different intensities (but same volume) in women. METHODS: Oxygen consumption (VO2, ml/min) was measured at rest, during weight training (WT), and during one-minute recovery periods between WT sets with a portable oxygen collection device (COSMEDTM K4b2) in nine women (age = 20.5 +/− .8 yr). Subjects performed at least three successive sets (separated by 1 min rest) of a seated chest press, supine leg press and a seated lat pull down at two intensities (70% and 85%) of maximum voluntary contraction (MVC) on two nonconsecutive days. The intensity and exercise sequence of the WT sessions was randomized and the sessions were separated by at least 48 hours. Total exercise volume, i.e., total pounds lifted (lbs x repetitions), was determined and held constant across intensities of WT so that only the intensity of work varied. Total exercise VO2 was determined as the oxygen consumption of all WT sets and all one-minute rest periods between sets. Net exercise VO2 (total exercise VO2 - rest VO2) and exercise energy expenditure (total exercise VO2 x 5 kcal/L O2) were calculated. RESULTS: There were no significant differences in the net exercise VO2 (7.5 +/− 2.1 vs. 8.0+/− 1.4L/min, P = .12) or energy expenditure (37.3 +/− 10.7 vs. 40.4+/− 7.4 kcal, P = .12) of WT at 70% versus 85% MVC. CONCLUSIONS: In women, total exercise oxygen consumption and energy expenditure appear to be similar across different intensities of WT when the total exercise volume (pounds lifted) is the same across WT intensities.