The Effect of High-Intensity Interval Training Periods on Morning Serum Testosterone and Cortisol Levels and Physical Fitness in Men Aged 35–40 Years

Abstract

Background: Intensive physical activity largely modulates resting concentrations of blood cortisol (C) and testosterone (T) and their molar ratio, which is defined as the anabolic–catabolic index and expressed as T/C × 102. The aim of the study is to evaluate the effect of the author’s high-intensity training program on T, C, T/C × 102, and selected physical fitness indices in men between 35 and 40 years of age. Methods: The experiment was conducted on a group of 30 healthy men, divided into control and experimental groups. The experimental group followed a high-intensity 8-week training program, which included three sessions per week, each of them lasting 1 h and consisting of intensive-interval exercises followed by strength circuit exercises. The 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 exercise test to determine maximal oxygen uptake (VO2max). Results: There were statistically significant increases in T (by 36.7%) and T/C × 102 (by 59%), while C somewhat dropped (by 12%) in the experimental group. No changes in the hormonal indices were found in the control group. After completing the experimental training, there were no statistically significant changes in aerobic capacity, but it improved muscle strength in the men studied. Conclusions: High-intensity interval training, continued over an 8-week period, modulates (significantly and positively) the balance between testosterone and cortisol levels and improves physical capacity in men aged 35–40 years.

The Effects of Different Exercise Intensities and Modalities on Cortisol Production in Healthy Individuals: A Review

“…As seen in previous studies, training adaptations seem to reduce the sensitivity of cortisol in individuals. 25,29 Similar results were observed by Ambrozy et al 42 who examined a decrease in the cortisol levels of men between the ages of 35-40 years old. The men performed eight weeks of HIIT and RT and demonstrated a more balanced testosterone/cortisol ratio.…”

“…An increase in testosterone indicated which training adaptation occurred and resulted in a blunting or loss in cortisol sensitivity. 25,42…”

Exercise-related changes in the anabolic index (testosterone to cortisol ratio) and serum amyloid A concentration in endurance and racehorses at different fitness levels

“…It is advisable for athletes to strive to increase their T/C ratio to optimize muscle protein metabolism and promote muscle growth during exercise ( 63 ). A significant decrease in the T/C index may indicate that the training intensity is too high for inexperienced horses, thus catabolic processes are prevailing, potentially leading to a decrease in skeletal muscle mass in extreme cases ( 55 ). Some research in humans has shown that there are no differences in the T/C ratio 12 h following high-intensity interval training (20 min of 15 s intervals of running at 110% of maximum oxygen consumption interspersed with 15 s of active rest at 40% of maximum oxygen consumption) ( 56 ).…”

“…There is a growing body of research indicating the usefulness of the testosterone-to-cortisol (T/C) ratio as a marker of physical fitness in humans (55)(56)(57)(58). It was postulated that the T/C ratio is more sensitive to the stress of training than either T or C measures alone.…”

A Shorter-Bout of HIIT Is More Effective to Promote Serum BDNF and VEGF-A Levels and Improve Cognitive Function in Healthy Young Men

“…Both interventions significantly evaluated testosterone level at post-HIIT, but after 30 min recovery, 20 min HIIT maintained higher level of testosterone than 30 min HIIT. Since testosterone shows anabolic effects and cortisol promotes catabolic effects, the T/C has been considered as a signal of the training activity is too high and catabolic processes prevail ( Ambroży et al, 2021 ). T/C is correlated with the duration and intensity of training, T/C decline indicates that the body is under high metabolic stress and accumulates fatigue ( Turner et al, 2017 ).…”