Concurrent Training Decreases Cortisol but Not Zinc Concentrations: Effects of Distinct Exercise Protocols

Objectives. To investigate the effects of distinct concurrent training (CT) protocols on zinc and cortisol concentrations and test the correlation between these blood variables. Methods. Samples of serum zinc and cortisol were assessed from 10 male subjects (27.1 ± 4.8 years old; BMI 25.38 ± 0.09) before and immediately after each study session: control (CS = no exercises), concurrent training 1 (CT1 = indoor cycling + strength training), and concurrent training 2 (CT2 = strength training + indoor cycle) with five days of interval between each. Results. There were no significant changes in zinc concentrations after the CS (Δ% = 8.45; p = 0.07), CT1 (Δ% = 4.77; p = 0.49), and CT2 (Δ% = −2.90; p = 0.12) sessions. Cortisol levels showed significant decrease after CS (Δ% = −6.02; p = 0.00), CT1 (Δ% = −26.32; p = 0.02), and CT2 (Δ% = −33.57; p = 0.05) sessions. There was a significant correlation between the variables only at CS (zinc post versus cortisol pre: r = 0.82 and cortisol post: r = 0.82). Conclusions. CT decreases cortisol concentrations regardless of the sequence performed. No changes were found in zinc concentrations after the study sessions. The reduction in serum cortisol concentrations appear to occur by a mechanism independent of the zinc status.