Cortisol and testosterone dynamics following exhaustive endurance exercise

Area of Science:

• Exercise Physiology
• Endocrinology
• Sports Science

Background:

• Prolonged endurance exercise significantly impacts hormonal balance, particularly cortisol (C) and testosterone (T).
• Inverse responses between C and T may affect post-exercise recovery.
• Understanding these dynamics is crucial for optimizing training and recovery strategies in athletes.

Purpose of the Study:

• To assess the concentration dynamics of cortisol (C) and free testosterone (fT) following an exhaustive endurance exercise session (EES).
• To determine the recovery time required for C and fT levels to return to baseline after EES.
• To investigate the relationship between C and fT concentrations immediately post-exercise.

Main Methods:

• 12 endurance-trained males completed a prolonged treadmill EES at their ventilatory threshold.
• Blood samples were collected at multiple time points: -48h, -24h, 0h (pre-EES), and +0h, +24h, +48h, +72h (post-EES).
• Measurements included cortisol, free testosterone, and blood glucose; data analyzed using repeated measures ANOVA.

Main Results:

• Cortisol levels significantly increased immediately post-EES and showed a transient drop below baseline at +24h.
• Free testosterone levels significantly decreased post-EES and remained suppressed at +24h and +48h.
• A significant negative correlation was observed between cortisol and free testosterone at +0h, indicating an inverse relationship.

Conclusions:

• Recovery of cortisol and free testosterone to baseline levels after exhaustive endurance exercise may require up to 48 hours and 72 hours, respectively.
• The inverse relationship between cortisol and free testosterone is most pronounced immediately after exercise.
• Further research with more frequent measurements is recommended to fully elucidate the time course of hormonal recovery.