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Updated: Oct 14, 2025

Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
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.
Introduction:
Strenuous exercise provokes increases in circulating cortisol levels. When the peak cortisol response to exercise occurs is a point of contention, as some research suggests the peak response coincides with the end of exercise while other indicate it is delayed and occurs during recovery.
Aim Of The Study:
This study examined when peak cortisol levels occur in response to intensive, exhausting exercise of a prolonged nature.
Methods:
Thirty-four healthy male subjects ran on a treadmill until volitional exhaustion. Blood specimens were analyzed for cortisol levels immediately at the end of exercise and at 30, 60, and 90 minutes into recovery.
Results:
A significantly greater number (25/34; i.e., 73.5%) of the peak cortisol responses occurred during the recovery period (at 30 - 90 minutes) after the subjects reached volitional exhaustion and had stopped exercising.
Conclusion:
The findings suggest that if researchers are interested in assessing the peak cortisol response to exhausting exercise they should continue blood sampling for approximately 1 hour into the recovery period.
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