MICT or HIIT ± RT Programs for Altering Body Composition in Postmenopausal Women.

Abstract

To compare body composition changes induced by moderate-intensity continuous training (MICT), high-intensity interval training (HIIT), or HIIT + resistance training (RT) programs (3 days/week, 12 weeks) in postmenopausal women with overweight/obesity, and to determine whether fat mass reduction is related to greater fat oxidation (FatOx).Participants (n=27) were randomized in three groups: MICT (40min at 55-60% of peak power output, PPO), HIIT (60 x 8s at 80-90% of peak heart rate, 12s active recovery), and HIIT + RT (HIIT + 8 whole-body exercises: 1 set of 8-12 repetitions). DXA was used to measure whole-body and abdominal/visceral fat mass (FM) and fat-free mass (FFM). FatOx was determined at rest, during a moderate-intensity exercise (40min at 50% of PPO), and for 20 minutes post-exercise, before and after training.Overall, energy intake and physical activity levels did not vary from the beginning to the end of the intervention. Body weight and total FM decreased in all groups over time, but significant abdominal/visceral FM losses were observed only in HIIT and HIIT + RT groups. When expressed in percentage, total FM, FFM, and muscle mass were significantly modified only by HIIT + RT training. FatOx did not change at rest, but increased similarly in the three groups during and after exercise. Therefore, the HIIT-induced greater FM loss was not related to higher FatOx during or after exercise.MICT or HIIT ± RT could be proposed to non-dieting postmenopausal women with overweight/obesity to decrease weight and whole-body FM. The HIIT programs were more effective than MICT in reducing abdominal/visceral FM. RT addition did not potentiate this effect, but increased the percentage of muscle mass.