Cortisol is a steroid hormone that affects a number of functions in the body. Exercise has many positive effects on the body, including affecting cortisol levels. Understanding how physical activity affects your cortisol levels can help you optimize and regulate this important hormone.
This article aims to help you better understand the relationship between exercise and cortisol levels.
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What is Cortisol?
Cortisol is a hormone that helps manage stress. This hormone is produced in your adrenal gland, specifically the zona fasciculata, and plays a role in several functions in your body, including:
- Regulation of metabolism
- Modulating immune response
- Supporting stress response
- Regulating blood pressure
- Influencing mood and behavior
- Supporting fetal development in pregnancy
- Regulating sleep-wake cycle
- Maintaining bone health
Cortisol is a steroid hormone from a class known as glucocorticoids. Your cortisol level is regulated by the hypothalamic-pituitary arsenal access (HPA-axis)[4], which involves the hypothalamus, pituitary glands, and adrenal glands. When you face a stressful situation, the body responds by activating the sympathetic nervous system. This activation causes the release of several hormones, including cortisol.[4]
Circadian rhythms, exercise, and some medications, such as steroids, also influence cortisol levels.[4] This means that if you measure your cortisol levels throughout the day, the levels will vary even if everything else stays the same. Other factors affecting your cortisol levels include age, gender, diet, and underlying fitness level.
The Impact of Exercise on Cortisol Levels
One of the factors that can influence cortisol levels in the body is exercise.
Types of Exercise that Affect Cortisol
Moderate to high-intensity exercise will increase the circulating cortisol levels by stimulating the hypothalamic-pituitary axis in the brain. Low-intensity exercise, especially over longer periods, does increase cortisol, but not to the same extent as more intense exercise. [6,7]
Timing and Duration
For people who are generally sedentary, the body initially responds to exercise with distress. However, over time and continued exercise exposure, the body accommodates and adapts, and exercise becomes a positive factor.[8]
Cortisol may aid in the body’s response and adaption to exercise. Cortisol promotes the creation of new proteins by increasing the amount of amino acids, the building blocks of proteins, available for new protein creation. It does this by breaking down other proteins, such as muscle fibers, in response to the stresses of exercise.[8]
As the body adapts to exercise, physical activity may reduce the overall stress response and decrease cortisol release in response to stress.[9,10]
Because exercise can stimulate your body’s stress responses in a controlled manner, it can potentially counteract those stress responses and train your body’s systems to work together.[11] This is one of the reasons that researchers believe that exercise helps people who have conditions associated with increased stress levels, such as depression.[9]
Exercise may help improve your body’s response to other types of stress. One study, which evaluated how the body responded to a stressor after a 30-minute bout of exercise, found that cortisol levels measured in response to exercise were inversely related to cortisol levels measured in response to the psychological or social stress administered after exercise.[12]
Studies also suggest that exercise may improve emotional response to stressful tasks and may counteract some of the emotional consequences of stress.[13]
Factors Influencing Exercise-Induced Cortisol Changes
There are many factors that can influence the effects of exercise on cortisol.
- Intensity: One of the primary factors that affects these changes is the intensity of exercise. Studies suggest that an exercise intensity requiring at least a 60% increase in the individual’s maximal oxygen update (VO2 max) for at least 10-15 minutes is required to increase cortisol levels above their normal resting levels in adults.[14] After maximal exhaustive exercise, cortisol levels may be 30-50% higher than baseline.[7]
- Duration: The duration of exercise can also affect the level of cortisol change. Even if you don’t reach maximal intensity levels, prolonged exercise may increase cortisol levels nearly as much as higher-intensity exercise.[7]
- Genetics: Genetic and physiological factors affect the individual’s response to cortisol. The exact factors are still being evaluated.[15] Gender may also play a role in cortisol levels, with men generally having a higher level than women.[16]
- Sleep and stress: Stress can raise cortisol levels, which can be further increased during exercise.[8] This is especially true with higher-intensity exercise.[14] Sleep can also affect cortisol levels. Sleep and stress affect each other. Cortisol levels may be impacted by conditions that cause poor sleep, such as sleep apnea or sleep deprivation.[17]
- Diet: Diet can also affect cortisol levels. One study showed that high-energy foods such as sugar may suppress the body's stress response.[18]
But what type of exercise is best, and how much? Experts generally recommend 150-200 minutes of moderate-intensity exercise per week.[13,19] Moderate-intensity exercise includes swimming, walking, gardening, water aerobics, tennis, and biking at a moderate pace.
Benefits of Regulated Cortisol Levels
Well-regulated cortisol levels may affect cognitive decline. The mechanisms for the effects of cortisol and other stress hormones on dementia and cognitive function are not fully understood, but the effects of stress hormones throughout lifespan may play a role in cognitive function.[20]
Cortisol is generally anti-inflammatory in nature, but chronic elevation can lead to increased production of inflammatory markers and a compromised immune response. Well-regulated cortisol levels may improve the overall immune system.[21]
Risks of Chronically Elevated Cortisol
Cortisol has many important bodily functions, so having well-regulated cortisol levels is important. Poorly regulated cortisol levels can have some negative effects on the body, such as [22]:
- Increased risk of cardiovascular disease
- Increased risk of stroke
- Weight gain (especially in the face and abdomen)
- Facial changes
- Swelling
- Decreased bone strength
- Increased risk of anxiety, depression, and memory problems
- Digestion problems and problems with gut microbiome.
- Sleep problems
- Increased glucose levels leading to or exacerbating diabetes
- Muscle weakness
Having well-regulated cortisol levels may help mitigate some of the adverse effects that dysregulated cortisol levels can cause.
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Key Takeaways
- Cortisol is a steroid hormone that plays important roles in many bodily functions
- Chronic elevation of cortisol can lead to adverse health effects
- Exercise can raise cortisol levels depending on the intensity and duration of activity
- Moderate-intensity exercise may improve the body’s ability to be resilient in stress
- Well-regulated cortisol levels may help support cognitive and immune function
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