INFLUENCE OF PROLONGED EXERCISE ON THE 24-HOUR FREE TESTOSTERONE - CORTISOL RATIO HORMONAL PROFILE

Area of Science:

• Exercise Physiology
• Endocrinology

Background:

• The free testosterone and cortisol ratio (fTC) is a key indicator of the anabolic and catabolic state.
• Understanding hormonal responses to exercise is crucial for training and recovery protocols.

Purpose of the Study:

• To investigate the temporal changes in the fTC ratio following prolonged endurance exercise.
• To determine if the fTC ratio exhibits delayed responses to intensive exercise.

Main Methods:

• A trained athlete underwent treadmill exercise at 70% VO2 max to volitional fatigue.
• Blood samples were collected serially over a 24-hour period.
• fTC ratio was analyzed to track changes during and after exercise.

Main Results:

• An initial increase in the fTC ratio was observed immediately post-exercise.
• A rapid decline in the fTC ratio followed the initial increase during early recovery.
• A significant, sustained secondary increase in the fTC ratio occurred approximately 8 hours into recovery.

Conclusions:

• The fTC ratio demonstrates a complex, biphasic response to prolonged endurance exercise.
• Delayed hormonal responses, occurring hours post-exercise, are characteristic of the fTC ratio.
• Exercise scientists must consider the timing of blood sampling for accurate fTC ratio interpretation.