From the Guidelines
High-intensity aerobic activity is known to increase cortisol levels in the body, as it is perceived as a stressor that triggers the release of cortisol from the adrenal glands. This physiological response is a normal part of the body's adaptation to exercise stress, helping to mobilize energy resources during intense physical activity 1. When engaging in vigorous aerobic activities, the body's cortisol response is typically proportional to the intensity and duration of the workout.
Key Points to Consider
- The increase in cortisol levels due to high-intensity aerobic activity is usually transient, with levels returning to baseline within a few hours after exercise.
- Regular moderate exercise can help regulate cortisol patterns over time, potentially leading to better hormonal balance.
- Excessive high-intensity training without adequate recovery may lead to chronically elevated cortisol levels, contributing to overtraining syndrome.
- It is advisable to include recovery days between high-intensity workouts and to combine intense training with lower-intensity activities for optimal hormonal balance.
Clinical Implications
The relationship between high-intensity aerobic activity and cortisol levels has implications for exercise prescription and management. While high-intensity interval training (HIIT) can be beneficial for certain targets of intervention, such as increasing VO2 peak 1, it should be prescribed judiciously, considering the individual's fitness level, health status, and ability to recover. Moderate-intensity continuous training remains a feasible and cost-effective option for many patients, especially those with chronic coronary syndromes 1. Ultimately, a personalized approach to exercise, taking into account the patient's preferences, abilities, and health conditions, is crucial for maximizing benefits while minimizing risks 1.
From the Research
High-Intensity Aerobic Activity and Cortisol Levels
- High-intensity aerobic activity has been shown to increase cortisol levels in several studies 2, 3, 4.
- A study published in the Journal of endocrinological investigation found that exercise at intensities of 60% and 80% of maximal oxygen uptake (VO2max) resulted in significant increases in cortisol levels, while low-intensity exercise (40% VO2max) did not 2.
- Another study published in the Journal of medical biochemistry found that high-intensity endurance exercise increased cortisol levels in both athletes and controls, but the response was more pronounced in controls 3.
- A study published in Health psychology and behavioral medicine found that aerobic exercise resulted in higher cortisol levels compared to meditation and yoga 4.
Factors Influencing Cortisol Response
- The time of day may influence the cortisol response to exercise, with one study finding that the magnitude of the increase in cortisol levels was greatest at 2400 h (midnight) compared to 0700 h (7 am) and 1900 h (7 pm) 5.
- The level of training may also influence the cortisol response, with one study finding that athletes had higher cortisol levels than controls, but the response to high-intensity endurance exercise was more pronounced in controls 3.
Contrasting Findings
- Not all studies have found a significant increase in cortisol levels in response to high-intensity aerobic activity. A study published in the Journal of clinical medicine found that six weeks of aerobic exercise training did not change cortisol reactivity in patients with major depressive disorder 6.