A comparison of the acute physiological responses to BODYPUMP™ versus iso-caloric and iso-time steady state cycling

Objectives: Given apparent consumer interest in calorie counting and arguably inadequate understanding of the differential effects of exercise modality despite equivalent caloric expenditure, we sought to quantify and compare the acute physiological responses within and between a BODYPUMP™ (BP) group-fitness class and steady-state cycling (CARDIO), matched for caloric cost (iso-caloric) and time (iso-time). Design: Acute cross-over study design. Methods: Twelve healthy recreationally active females (30.1 ± 5.8 years [mean ± SD]) completed cardiorespiratory fitness and strength tests. Subsequently, BP and CARDIO were performed on separate days in randomized order, during which heart rate was monitored continuously, and rating of perceived exertion solicited. Blood samples were collected immediately pre- and post-trial and at 45 min post-trial for determination of human growth hormone (HGH), interleukin 6 (IL-6), and cortisol. Lactate (BL) was determined from capillary blood. All outcome measures were analyzed for within-, and between-trial differences. Results: HGH, IL-6 and BL were significantly elevated immediately post-trial for both BP and cycling; the elevation for HGH and BL was significantly greater for BP than CARDIO. IL6 remained elevated at 45 min post-trial for both exercise modes, but there was no significant between trial difference. Mean heart rate for both trials was 68% of individually determined maximum heart rate, and predicted VO₂ during BP was 14.9 ± 5.2 ml kg min, or 46.7 ± 19.4%VO_2peak. Mean load self-selected by participants during BP ranged from 21 ± 7%1RM to 32 ± 9%1RM across four exercises. Conclusions: These results indicate that BP provided some more potent acute physiological effects than iso-caloric and iso-time steady-state cycling.