Cortisol is a steroid hormone, often referred to as the stress hormone, produced by the adrenal gland in response to stress. It has earned its nickname because it is released in response to emotional and physical stress.
Being a key component in the body’s stress handling ability, it acts on many vital functions in our body to enable energy release, effective use of that energy and an overall boost of our senses in order to survive the immediate threat.
Examples of processes that cortisol is involved in include:
- Regulation of blood pressure
- Anti-inflammatory response
- Regulation of blood sugar levels
- Regulation of the immune system
- Control of the circadian rhythm
Measuring cortisol can be useful when monitoring and diagnosing medical conditions that may affect the production, effectiveness, or breakdown of cortisol. Such conditions include Cushing's syndrome, Addison's disease, and diabetes. Contrary to popular belief, cortisol is not a straightforward measure of stress levels. Instead, cortisol is measured to assess whether there are abnormal deviations that may reveal underlying diseases and medical conditions.
Important note: Cortisol levels can be influenced by various factors, including sleep patterns, medication, time of day, and food intake, among others. Therefore, understanding the significance of a cortisol value requires other clinical findings such as additional test results and symptoms before it can be properly interpreted by a doctor.
When discussing performance and training, cortisol is directly dependent on training intensity. The risk of overtraining is higher when cortisol levels are elevated, which can be interpreted as a sign of regularly exercising at high intensity and possibly neglecting recovery. Cortisol is also used as a marker for breakdown, or catabolism. This is the opposite of building up, also known as anabolism. In the body, anabolic hormones such as testosterone and growth hormone can counteract the effects of cortisol. Therefore, cortisol can also be used as a marker to assess the relationship between breakdown and building up, when compared, for example, with testosterone. Chronic stress will similarly decrease anabolic capacity, increasing breakdown, the risk of overtraining, and impairing performance.
Low cortisol levels, also known as hypocortisolism, simply mean that you have an underproduction of cortisol. This can be harmful since cortisol plays an essential role in functions such as metabolism and the immune system. If you show low levels of cortisol, it is important to identify underlying causes as soon as possible.
There are multiple underlying reasons for why this may emerge, such as Addison’s disease, pituitary gland dysfunctions and long-term use of corticosteroids.
Low cortisol levels may interfere with blood glucose balances and cause your blood pressure and thyroid gland activity to decrease. This may result in fatigue, weakened immune system and sleep disorders.
High cortisol levels, also known as hypercortisolism or Cushing’s syndrome, mean that you have an overproduction of cortisol. This overproduction can be caused by a variety of reasons, including structural changes in the adrenal glands and chronic stress.
High circulating cortisol levels may result in high blood glucose levels, increasing the risk for diabetes. It may also result in high blood pressure, sleep disorders, decreased muscle mass and increased fat mass. All of which increase the overall risk of cardiovascular disease.
Important note: It is important to identify underlying causes of elevated cortisol levels as soon as possible, as chronic increases may lead to conditions like diabetes and osteoporosis.