What is cortisol?
Cortisol is a glucocorticoid hormone that your adrenal glands produce and release.
Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.
Glucocorticoids are a type of steroid hormone. They suppress inflammation in all of your bodily tissues and control metabolism in your muscles, fat, liver and bones. Glucocorticoids also affect sleep-wake cycles.
Cortisol is an essential hormone that affects almost every organ and tissue in your body. It plays many important roles, including:
- Regulating your body’s stress response.
- Helping control your body’s use of fats, proteins and carbohydrates, or your metabolism.
- Suppressing inflammation.
- Regulating blood pressure.
- Regulating blood sugar.
- Helping control your sleep-wake cycle.
Your body continuously monitors your cortisol levels to maintain steady levels (homeostasis). Higher-than-normal or lower-than-normal cortisol levels can be harmful to your health.
Is cortisol a stress hormone?
Cortisol is widely known as the “stress hormone.” However, it has many important effects and functions throughout your body aside from regulating your body’s stress response.
It’s also important to remember that, biologically speaking, there are multiple different kinds of stress, including:
- Acute stress: Acute stress happens when you’re in sudden danger within a short period of time. For example, barely avoiding a car accident or being chased by an animal are situations that cause acute stress.
- Chronic stress: Chronic (long-term) stress happens when you experience ongoing situations that cause frustration or anxiety. For example, having a difficult or frustrating job or having a chronic illness can cause chronic stress.
- Traumatic stress: Traumatic stress happens when you experience a life-threatening event that induces fear and a feeling of helplessness. For example, experiencing an extreme weather event, such as a tornado, or experiencing war or sexual assault can cause traumatic stress. In some cases, these events can lead to post-traumatic stress disorder (PTSD).
Your body releases cortisol when you experience any of these types of stress.
What does cortisol do to my body?
Almost all tissues in your body have glucocorticoid receptors. Because of this, cortisol can affect nearly every organ system in your body, including:
- Nervous system.
- Immune system.
- Cardiovascular system.
- Respiratory system.
- Reproductive systems (female and male).
- Musculoskeletal system.
- Integumentary system (skin, hair, nails, glands and nerves).
More specifically, cortisol affects your body in the following ways:
- Regulating your body’s stress response: During times of stress, your body can release cortisol after releasing its “fight or flight” hormones, such as adrenaline, so you continue to stay on high alert. In addition, cortisol triggers the release of glucose (sugar) from your liver for fast energy during times of stress.
- Regulating metabolism: Cortisol helps control how your body uses fats, proteins and carbohydrates for energy.
- Suppressing inflammation: In short spurts, cortisol can boost your immunity by limiting inflammation. However, if you have consistently high levels of cortisol, your body can get used to having too much cortisol in your blood, which can lead to inflammation and a weakened immune system.
- Regulating blood pressure: The exact way in which cortisol regulates blood pressure in humans is unclear. However, elevated levels of cortisol can cause high blood pressure, and lower-than-normal levels of cortisol can cause low blood pressure.
- Increasing and regulating blood sugar: Under normal circumstances, cortisol counterbalances the effect of insulin, a hormone your pancreas makes, to regulate your blood sugar. Cortisol raises blood sugar by releasing stored glucose, while insulin lowers blood sugar. Having chronically high cortisol levels can lead to persistent high blood sugar (hyperglycemia). This can cause Type 2 diabetes.
- Helping control your sleep-wake cycle: Under regular circumstances, you have lower cortisol levels in the evening when you go to sleep and peak levels in the morning right before you wake up. This suggests that cortisol plays a significant role in the initiation of wakefulness and plays a part in your body’s circadian rhythm.
Optimum cortisol levels are necessary for life and for maintaining several bodily functions. If you have consistently high or low cortisol levels, it can have negative impacts on your overall health.
How does my body control cortisol levels?
Your body has an elaborate system to regulate your cortisol levels.
Your hypothalamus, a small area of your brain involved in hormonal regulation, and your pituitary gland, a tiny gland located below your brain, regulate the production of cortisol in your adrenal glands. When the levels of cortisol in your blood fall, your hypothalamus releases corticotropin-releasing hormone (CRH), which directs your pituitary gland to produce adrenocorticotropic hormone (ACTH). ACTH then stimulates your adrenal glands to produce and release cortisol.
In order to have optimal levels of cortisol in your body, your hypothalamus, pituitary gland and adrenal glands must all be functioning properly.
What tests can check cortisol levels?
Healthcare providers can measure your cortisol levels through blood, urine (pee) or saliva (spit) tests. They will determine which test is best depending on your symptoms.
What are normal cortisol levels?
The level of cortisol in your blood, urine and saliva normally peaks in the early morning and declines throughout the day, reaching its lowest level around midnight. This pattern can change if you work a night shift and sleep at different times of the day.
For most tests that measure cortisol levels in your blood, the normal ranges are:
- 6 a.m. to 8 a.m.: 10 to 20 micrograms per deciliter (mcg/dL).
- Around 4 p.m.: 3 to 10 mcg/dL.
Normal ranges can vary from lab to lab, time to time and person to person. If you need to get a cortisol level test, your healthcare provider will interpret your results and let you know if you need to get further testing.
What causes high levels of cortisol?
Experiencing abnormally high levels of cortisol (hypercortisolism) for an extended period of time is usually considered Cushing’s syndrome, which is a rare condition. Causes of higher-than-normal cortisol levels and Cushing’s syndrome include:
- Taking large amounts of corticosteroid medications, such as prednisone, prednisolone or dexamethasone, for treatment of other conditions.
- Tumors that produce adrenocorticotropic hormone (ACTH). These are usually found in your pituitary gland. More rarely, neuroendocrine tumors in other parts of your body such as your lungs can cause high cortisol levels.
- Adrenal gland tumors or excessive growth of adrenal tissue (hyperplasia), which cause excess production of cortisol.
What are the symptoms of high cortisol levels?
The symptoms of Cushing’s syndrome depend on how elevated your cortisol levels are. Common signs and symptoms of higher-than-normal cortisol levels include:
- Weight gain, especially in your face and abdomen.
- Fatty deposits between your shoulder blades.
- Wide, purple stretch marks on your abdomen (belly).
- Muscle weakness in your upper arms and thighs.
- High blood sugar, which often turns into Type 2 diabetes.
- High blood pressure (hypertension).
- Excessive hair growth (hirsutism) in people assigned female at birth.
- Weak bones (osteoporosis) and fractures.
What causes low levels of cortisol?
Having lower-than-normal cortisol levels (hypocortisolism) is considered adrenal insufficiency. There are two types of adrenal insufficiency: primary and secondary. The causes of adrenal insufficiency include:
- Primary adrenal insufficiency: Primary adrenal insufficiency is most commonly caused by an autoimmune reaction in which your immune system attacks healthy cells in your adrenal glands for no known reason. This is called Addison’s disease. Your adrenal glands can also become damaged from an infection or blood loss to the tissues (adrenal hemorrhage). All of these situations limit cortisol production.
- Secondary adrenal insufficiency: If you have an underactive pituitary gland (hypopituitarism) or a pituitary tumor, it can limit ACTH production. ACTH signals your adrenal glands to make cortisol, so limited ACTH results in limited cortisol production.
You can also have lower-than-normal cortisol levels after stopping treatment with corticosteroid medications, especially if you stop taking them very quickly after a long period of use.
What are the symptoms of low cortisol levels?
Symptoms of lower-than-normal cortisol levels, or adrenal insufficiency, include:
How can I reduce my cortisol levels?
If you have Cushing’s syndrome (very high levels of cortisol) you’ll need medical treatment to lower your cortisol levels. Treatment usually involves medication and/or surgery. You’ll also need medical treatment if you have lower-than-normal cortisol levels.
In general, though, there are several everyday things you can do to try to lower your cortisol levels and keep them at optimal ranges, including:
- Get quality sleep: Chronic sleep issues, such as obstructive sleep apnea, insomnia or working a night shift, are associated with higher cortisol levels.
- Exercise regularly: Several studies have shown that regular exercise helps improve sleep quality and reduce stress, which can help lower cortisol levels over time.
- Learn to limit stress and stressful thinking patterns: Being aware of your thinking pattern, breathing, heart rate and other signs of tension helps you recognize stress when it begins and can help you prevent it from becoming worse.
- Practice deep breathing exercises: Controlled breathing helps stimulate your parasympathetic nervous system, your “rest and digest” system, which helps lower cortisol levels.
- Enjoy yourself and laugh: Laughing promotes the release of endorphins and suppresses cortisol. Participating in hobbies and fun activities can also promote feelings of well-being, which may lower your cortisol levels.
- Maintain healthy relationships: Relationships are a significant aspect of our lives. Having tense and unhealthy relationships with loved ones or coworkers can cause frequent stress and raise your cortisol levels.
When should I see my doctor about my cortisol levels?
If you experience symptoms of Cushing’s syndrome or adrenal insufficiency, contact your healthcare provider.
If you’re concerned about your daily stress levels, talk to your provider about steps you can take to minimize your stress and stay healthy.
A note from Cleveland Clinic
Cortisol is an essential hormone that impacts several aspects of your body. While there are several things you can do to try to limit your stress, and therefore manage your cortisol levels, sometimes having abnormally high or low levels of cortisol is out of your control.
If you experience symptoms of high or low cortisol levels, such as weight gain or loss and high or low blood pressure, respectively, it’s important to contact your healthcare provider. They can run some simple tests to see if your adrenal glands or pituitary gland are responsible for your symptoms.
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