The effects of exercise training under mild hypoxic conditions on body composition and circulating adiponectin in postmenopausal women

Purpose: This study aimed to examine the effects of exercise training under mild hypoxic conditions on body composition and circulating adiponectin levels in postmenopausal women. Methods: Fourteen postmenopausal women (56 ± 1 years) were assigned to a normoxic (N group) or hypoxic (H group) exercise group. Aquatic exercise training was performed at an intensity of 50% peak oxygen uptake level for 30 min per training session, 4 days per week, for 8 weeks. The H group performed the exercise under hypobaric hypoxic conditions, which corresponds to 2000 m above sea level, and each participant was exposed to these conditions for 2 h per session. Results: After the training, no significant changes were observed in any of the measured values for the N group. Conversely, body mass (57·3 ± 2·5 to 54·5 ± 2·3 kg), body mass index (24·6 ± 0·8 to 23·4 ± 0·7 kg m⁻²), body fat (30·7 ± 1·9 to 28·1 ± 1·6%) and preperitoneal fat thickness as an index of visceral fat accumulation (10·3 ± 1·7 to 6·4 ± 1·0 mm) significantly reduced only in the H group. Circulating adiponectin levels significantly increased (9·5 ± 1·8 to 11·4 ± 2·0 μg ml⁻¹), and the changes in adiponectin were significantly correlated with those in body mass (r = −0·81) and body mass index (r = −0·85). Conclusions: These results suggest that exercise training under mild hypoxic conditions could more effectively reduce body fat and increase adiponectin levels in postmenopausal women in a shorter period, than exercise training in normoxia.