Physiological adaptations of active postmenopausal women and matched men to the multi-day Sardinia Selvaggio Blu wild trek: a gender-comparative pilot study

Purpose: To evaluate the effects of wild trekking by examining, in postmenopausal women, the physiological adaptations to an intensive 5-day wild trek and comparing their responses to those displayed by a group of men of comparable age, training status and mountaineering skills. Methods: Six healthy, active postmenopausal women in their sixth decade of life participated in the study. Six men of comparable age and training status were also enrolled for gender-based comparisons. The participants traversed the Selvaggio Blu wild trek (Sardinia, Italy) completing a total of 56 km, for an overall height differential of 14,301 m. During all 5-day trek, subjects were supervised by two alpine guides. Changes in body composition, cardiorespiratory fitness, and metabolic patterns of energy expenditure were evaluated before and after the intervention. Results: Total energy expenditure during the trek was significantly higher (p = 0.03) in women (12.88 ± 3.37 kcal/h/kg) than men (9.27 ± 0.89 kcal/h/kg). Extracellular (ECW) and intracellular water (ICW) increased significantly following the trek only in women (ECW: - 3.8%; p = 0.01; ICW: + 3.4%; p = 0.01). The same applied to fat-free mass (+ 5.6%; p = 0.006), fat mass (- 20.4%; p = 0.006), skeletal muscle mass (+ 9.5%; p = 0.007), and appendicular muscle mass (+ 7.3%; p = 0.002). Peak VO2/kg (+ 9.4%; p = 0.05) and fat oxidation (at 80 W: + 26.96%; p = 0.04; at 100 W: + 40.95%; p = 0.02; at 120 W: + 83.02%; p = 0.01) were found increased only in women, although no concurrent changes in partial pressure of end-tidal CO2 (PETCO2) was observed. Conclusions: In postmenopausal women, a 5-day, intensive and physically/technically demanding outdoor trekking activity led to significant and potentially relevant changes in body composition, energy balance and metabolism that are generally attained following quite longer periods of training.