The response of serum leptin, cortisol and zinc concentrations to concurrent training

OBJECTIVE To investigate the effects of concurrent training (CT) on serum leptin, cortisol and zinc concentrations in physically active adults. DESIGN Ten subjects aged (27.1±4.8 years, BMI 25.49 ± 2.65) were recruited to participate in three sessions: control session (CS), concurrent training 1 (CT1) and concurrent training 2 (CT2) sessions with five days of resting between them. In each session blood samples for leptin, cortisol and zinc determination were collected. CT1 session included indoor cycling class followed by strength training. CT2 session included strength training, followed by indoor cycling class. In CS there were no exercises. The Shapiro-Wilk test, repeated ANOVA test and Tukey Post-Hoc test were used. RESULTS There was a reduction in leptin levels after CT1 (Δ% = −16.04; p = 0.05) and CT2 (Δ% = −8.54; p = 0.02). Cortisol also showed a reduction after CT1 (Δ% = −26.32; p = 0.02) and CT2 (Δ% = −33.57; p = 0.05), whereas zinc did not show any significant alterations after any of the training sessions. There was also significant difference for the leptin and cortisol values between CT1 and CT2. CONCLUSIONS CT promoted reduction in serum leptin and cortisol levels independently of the training order, while no significant changes in zinc concentrations were observed.