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Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
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PEAK CORTISOL RESPONSE TO EXHAUSTING EXERCISE: EFFECT OF BLOOD SAMPLING SCHEDULE
W Daly1, C Seegers1, S Timmerman1
1Endocrine Section - Applied Physiology Laboratory, University of North Carolina, Chapel Hill, North Carolina, USA.
Medicina Sportiva (Krakow, Poland : English Ed.)
|November 1, 2021
Summary
Peak cortisol levels after strenuous exercise typically occur during the recovery period, not immediately after exertion. Researchers should measure cortisol for up to an hour post-exercise to capture the true peak response.
Area of Science:
- Exercise Physiology
- Endocrinology
- Sports Science
Background:
- Strenuous exercise significantly elevates circulating cortisol levels.
- The precise timing of peak cortisol response post-exercise remains debated, with conflicting evidence on whether it occurs immediately after or during recovery.
Purpose of the Study:
- To determine the timing of peak cortisol levels following intensive, prolonged, and exhaustive exercise.
Main Methods:
- Thirty-four healthy males performed treadmill running to volitional exhaustion.
- Blood samples were collected immediately post-exercise and at 30, 60, and 90 minutes into the recovery phase.
- Serum cortisol concentrations were analyzed for each time point.
Main Results:
- The majority of subjects (73.5%, 25/34) exhibited their peak cortisol levels during the recovery period (30-90 minutes post-exercise).
- Peak cortisol response was significantly delayed beyond the cessation of exercise for most participants.
Conclusions:
- To accurately assess the peak cortisol response to exhaustive exercise, blood sampling should extend into the recovery period, ideally for about one hour.
- Current research protocols may underestimate the physiological cortisol response by not sampling sufficiently into recovery.
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