Sexual dimorphism in exercise-induced response on steroid hormones to a 24-week supervised concurrent training intervention

Background: Steroid hormones are key mediators of adaptative responses to exercise, a stimulus that may concurrently affect their blood concentrations. However, the chronic endocrine adaptations and whether these potential changes are dependent on exercise intensity remain undetermined. Moreover, it is also unknown if the exercise-induced effects on steroid hormonal status are related to the participant' sex.

Methods: This study aimed to investigate the intensity effects of a 24-week supervised concurrent training intervention on steroid hormones in sedentary young men and women. A total of 106 untrained young adults (68% women) aged 18-25 years were randomly assigned to one of the three groups: (I) Control group (no exercise; n = 35); (II) Ex-Moderate group (concurrent training at moderate intensity; n = 36); (III) Ex-Vigorous group (concurrent training at vigorous intensity; n = 35). Steroid hormones (i.e. cortisol, testosterone and dehydroepiandrosterone sulfate (DHEAS)) were measured in plasma through a chemiluminescent method. Body composition parameters were determined using a dual-energy X-ray absorptiometry scanner.

Results: No significant changes in steroid hormones levels were observed after the intervention (all p ≥ .129). However, a time x group interaction was noted in the testosterone/cortisol ratio (T/C ratio) only in women (p = .044). Concretely, our data showed a significant decrement of T/C ratio in both the Ex-Moderate group and in the Ex-Vigorous compared with the control group (Δ = -24.2 ± 2.0% and Δ = -38.9 ± 45.4%, respectively).

Conclusion: Our 24-week supervised concurrent training intervention showed no significant changes in steroid hormone levels. However, a significant decrement of T/C ratio was observed only in women, indicating a sexual dimorphism in the effect on T/C ratio.