Acute metabolic responses after continuous or interval exercise in postmenopausal women with overweight or obesity.

Dupuit, Marine; Boscaro, Audrey; Bonnet, Alban; Bouillon, Patrice; Bruno, Pereira; Morel, Claire; Rance, Mélanie; Boisseau, Nathalie

This pilot study compared the effects of acute high-intensity intermittent exercise (HIIE) and moderate-intensity continuous exercise (MICE) on post-exercise VO2 , fat utilization, and 24h-energy balance to understand the mechanism of higher fat mass reduction observed after high-intensity interval training in postmenopausal women with overweight/obesity. 12 fasted women (59.5±5.8 years; BMI: 28.9±3.9 kg.m-2 ) completed three isoenergetic cycling exercise sessions in a counterbalanced, randomized order: i) MICE [35min at 60-65% of peak heart rate, HRmax ], ii) HIIE 1 [60 × (8s cycling-12s recovery) at 80-90% of HRmax ] and iii) HIIE 2 [10 × 1min at 80-90% of HRmax - 1min recovery]. Then, VO2 and fat utilization measured at rest and during the 2h post-exercise, enjoyment, perceived exertion and appetite recorded during the session and energy intake (EI) and energy expenditure (EE) assessed over the next 24h were compared for the three modalities. Overall, fat utilization increased after exercise. No modality effect or time-modality interaction were observed concerning VO2 and fat oxidation rate during the 2h post-exercise. The two exercise modalities did not induce specific EI and EE adaptations, but perceived appetite scores at 1h post-exercise were lower after HIIE 1 & 2 than MICE. Perceived exertion was higher during HIIE 1 & 2 than MICE, but enjoyment did not differ among modalities. The acute HIIE responses did not allow explaining the greater fat mass loss observed after regular high-intensity interval training in postmenopausal women with overweight/obesity. More studies are needed to understand the mechanisms involved in such adaptations.