Intensive physical activity greatly modulates the resting concentrations of cortisol (C) and testosterone (T) in the blood and their molar ratio, which is defined as the anabolic-catabolic index and is expressed as T / C × 102.
The results of a study have recently been published (Ambrozy et al, 2021; J Clin Med 15-May; doi: 10.3390 / jcm10102143) with the aim to evaluate the effect of a HIIT (high intensity interval training) program on concentrations of T, C, T / C × 102 and selected indices of physical fitness in men between 35 and 40 years old.
A group of 30 healthy men participated, divided into control and experimental groups. The experimental group followed an 8-week high-intensity training program, which included three sessions per week, each of which lasted 1 hour and consisted of intensive interval exercises followed by resistance circuit exercises. Controls did not change their previous recreational physical activity. T, C and T / C × 102 were measured before and after the experiment for all participants. Physical performance was examined using a standardized laboratory stress test to determine maximal oxygen uptake (VO2max).
The results showed statistically significant increases in T (by 36.7%) and T / C × 102 (by 59%), while C decreased somewhat (by 12%) in the experimental group. No changes were found in hormonal indices in the control group. After completing the experimental training, there were no statistically significant changes in aerobic capacity, but muscle strength did improve in the men studied.
The authors concluded that HIIT, applied over a period of 8 weeks, modulates (significantly and positively) the balance between testosterone and cortisol levels and improves physical capacity in men aged 35 to 40 years.
JL. Chicharro (PhD) Opinion:
HIIT, in practically any of its versions, is associated with very positive physiological changes to improve performance and health. Most of these effects are the consequence of the sympathetic-adrenal stimulus associated with the high intensity characteristic of this training modality.