Cortisol and testosterone dynamics following exhaustive endurance exercise
Anderson, T., Lane, A.R., & Hackney, A.C. (2016). European Journal of Applied Physiology, 116(8), 1503-1509. doi:10.1007/s00421-016-3406-y
Take Home Message: Following high-intensity endurance exercise, recovery may require 48-72 hours for cortisol and testosterone to return back to resting levels.
Endurance running produces physiological stress to the body, resulting in neuroendocrine (hormonal) responses. Specifically, cortisol (a hormone that is released in response to stress on the body and can break down muscle tissue), increases and testosterone (a hormone that builds up muscles tissue), decreases following intense exercise. Due to this shift, the body is breaking tissue down more than it is laying down, which may negatively affect recovery status; however, research has only been conducted to assess the acute stage and the longer lasting effects of the hormonal imbalance during recovery has not been established. The long-term hormone responses are important to monitor in order to prevent and detect overtraining in athletes. Therefore, the authors evaluated 12 elite male runners following a bout of exhaustive exercise (~97 min) to assess cortisol and testosterone levels and the effect to their recovery status. Baseline maximum oxygen consumption and ventilator threshold were measured to determine appropriate training intensity. Seven days later, athletes returned to the lab for the completion of the exhaustive exercise session. The athletes rested in a supine position for 30 minutes before providing their resting blood sample. The athletes were fitted with a heart rate monitor, and allowed to warm-up prior to beginning the exhaustive run (100% of ventilator threshold) on the treadmill until fatigue. Following a five-minute cool down, post-exercise blood samples were collected. The athletes reported back to the lab at the same time of day 24, 48, and 72 hours after the endurance exercise session, where blood samples were drawn again. Hormonal concentrations of cortisol and free testosterone were assessed in all samples. Analysis revealed a significant decrease in free testosterone that persisted up to 48 hours post-exhaustive exercise before returning to baseline values at 72 hours. Furthermore, there were significant increases in cortisol, which returned to baseline levels at 48 hours post-exhaustive exercise. There was a significant negative correlation between cortisol and free testosterone levels immediately following the exhaustive exercise.
This study attempted to provide an understanding of the effects of exhaustive exercise on cortisol and testosterone concentrations during recovery. Findings suggest that 48-72 hours of recovery may be required to return cortisol and testosterone to resting levels. Understanding hormonal responses and the proper recovery plays an essential role in athletic performance and preventing overtraining. Athletes training at a high intensity may be compromising muscular growth, power, and development, as well as overall sport performance, if coaches do not allot sufficient recovery periods. Therefore, coaches and health professionals may use cortisol and testosterone assessments to monitor their athletes’ recovery status in order to install a training progression that allows the athletes to have proper recovery time. It would be interesting to observe whether similar hormonal patterns occur when athletes engage in resistance training. While not all coaches may have the capability of drawing blood to monitor these hormones, coaches may consider avoiding intense training on consecutive days. Additionally, coaches may allow their athletes 48-72 hours to recovery before completing another high-intensity exercise session. This would enable athletes to perform at their full potential, while reducing possible risk of overtraining.
Questions for Discussion: How may these results change/remain the same if we look at resistance training rather than endurance exercise? How could coaches modify their athletes’ training if they observe low testosterone and high cortisol levels?
Written by: Jennifer Fields
Reviewed by: Jane McDevitt
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