Effects of very short rest periods on testosterone to cortisol ratio during heavy resistance exercise in men

The ratio between testosterone and cortisol concentration (Ts/Co ratio) is frequently used as an index of the stress level in exercise training. Changes in this ratio are responsible for several training responses such as hypertrophy and strength gain. So the purpose of this study was to investigate the effect of 4 sets of bench press and squat to failure with %85 of 1RM using different rest intervals of 60 (P60), 90 (P90) and 120 (P120) second on testosterone to cortisol ratio in resistance trained men. Ten recreationally resistance-trained men (age, 22±2 years; weight, 84±8kg; height, 178.5±8.5; at least 1 year of resistance exercise [RE] experience) performed RE protocols on randomized separating session. Blood draws occurred at pre-exercise (Pre); immediately after (Post) and 30min after the end of the session (30Post) for measurement serum testosterone and cortisol concentrations. The results of this study indicated that Ts/Co ratio in P60 trail was significantly lower at post and 30min post compare to pre-exercise (p≤0.05). The Ts/Co ratio at post exercise was significantly higher in P120 than P60 and P90 (p≤0.05), but no difference was found between P60 and P90. The data indicate that long rest period between sets in RE to failure resulted in a grater increase in Ts/Co ratio than short rest period between sets in RE. The enhanced in Ts/Co ratio by long rest period between sets, indicating an augmented anabolic state to RE in resistance trained men.