Comparison of High-Intensity Interval Training and Moderate-to-Vigorous Continuous Training for Cardiometabolic Health and Exercise Enjoyment in Obese Young Women: A Randomized Controlled Trial

Objective The aim of this study was to compare the effects of 5-week high-intensity interval training (HIIT) and moderate-to-vigorous intensity continuous training (MVCT) on cardiometabolic health outcomes and enjoyment of exercise in obese young women. Methods A randomized controlled experiment was conducted that involved thirty-one obese females (age range of 18-30) randomly assigned to either HIIT or MVCT five-week training programs. Participants in HIIT condition performed 20 min of repeated 8 s cycling interspersed with 12 s rest intervals, and those in MVCT condition cycled continuously for 40 min at 60-80% of peak oxygen consumption ((V)over dotO(2peak)), both for four days in a week. Outcomes such as (V)over dotO(2peak), body composition estimated by bioimpedance analysis, blood lipids, and serum sexual hormones were measured at pre-and post-training. The scores of Physical Activity Enjoyment Scale (PAES) were collected during the intervention. Results After training, (V)over dotO(2peak) increased significantly for both training programs (9.1% in HIIT and 10.3% in MVCT) (p = 0.010, eta(2) = 0.41). Although MVCT group had a significant reduction in total body weight (TBW, -1.8%, p = 0.034), fat mass (FM, -4.7%, p = 0.002) and percentage body fat (PBF, -2.9%, p = 0.016), there were no significant between-group differences in the change of the pre- and post-measures of these variables. The HIIT group had a higher score on PAES than the MVCT group during the intervention. For both conditions, exercise training led to a decline in resting testosterone and estradiol levels, but had no significant effect on blood lipids. Conclusion Both HIIT and MVCT are effective in improving cardiorespiratory fitness and in reducing sexual hormones in obese young women; however, HIIT is a more enjoyable and time-efficient strategy. The mild-HIIT protocol seems to be useful for at least maintaining the body weight among sedentary individuals.