Cortisol: what this hormone is, what it does, and what it affects

Cortisol is often called the stress hormone, and for most people that is where their familiarity with it ends. Yet it affects almost every organ and tissue in the body — from blood pressure and glucose levels to metabolism and inflammation. Let's look at what this substance is, where it is produced, and what the numbers in a test mean.

What cortisol is and where it is produced

Cortisol is a hormone produced by the adrenal glands, two small glands located above the kidneys. Hormones serve as chemical messengers: they circulate in the blood and control the work of specific cells and organs.

Cortisol production is regulated by the pituitary gland, a gland in the brain. It produces the hormone ACTH, which tells the adrenal glands how much cortisol to synthesize. That is why a malfunction can occur at two levels: in the adrenal glands themselves or in the pituitary gland.

Key point: cortisol is made by the adrenal glands, and the pituitary gland gives them the command.

What cortisol does in the body

Cortisol affects almost every organ and every tissue. Its normal functions are as follows:

• it helps the body respond to stress — hence its other name, the "stress hormone";
• it reduces inflammation and swelling;
• it controls blood glucose levels and metabolism — how the body uses food for energy;
• it is involved in regulating blood pressure.

Key point: cortisol is not only needed during stress — it is involved every day in metabolism, inflammation, and blood pressure regulation.

How cortisol affects the body: excess and deficiency

While cortisol is within the normal range, its work goes unnoticed. With an excess or deficiency, the condition can be serious, and without treatment it does not resolve.

Excess cortisol — Cushing's syndrome. This is a rare condition, most often associated with long-term use of high doses of steroid medications, such as hydrocortisone or prednisolone. Less often, the cause is a small benign growth in the pituitary gland or adrenal glands, or a cortisol-producing tumor. Symptoms develop gradually: excess fat on the neck, upper back, chest, and abdomen with thin arms and legs, a red round face, skin that bruises easily, wide stretch marks on the abdomen, thighs, chest, and under the arms, weakness in the muscles of the shoulders and thighs, decreased libido, irritability, anxiety or low mood, menstrual irregularities, excessive hair growth. In women, the syndrome occurs noticeably more often than in men; in children it is rare and manifests as obesity and stunted growth.

Cortisol deficiency occurs in Addison's disease and secondary adrenal insufficiency. In that case, a person is troubled by prolonged fatigue, muscle weakness, loss of appetite and weight, and abdominal pain.

Without treatment, both excess and deficiency of cortisol can be very serious. With untreated Cushing's syndrome, heart attack and stroke, high blood pressure, type 2 diabetes, blood clots, bone weakening, and kidney stones are possible.

Key point: both excess and deficiency of the hormone cause characteristic symptoms, and the cause often lies in medications, the pituitary gland, or the adrenal glands.

What a cortisol test shows

The test measures the amount of cortisol in blood, urine, or saliva. It is ordered to confirm or rule out Cushing's syndrome, Addison's disease, and secondary adrenal insufficiency, as well as to monitor the treatment of these conditions.

Cortisol changes throughout the day, so blood is usually taken twice: in the morning, when the level is highest, and around 4 p.m., when it is noticeably lower. In other cases, you may be asked to collect urine over 24 hours or several saliva samples at home at different times — this shows how the level rises and falls. Stress and exertion raise cortisol, so you may need to rest before the test; the medical facility provides preparation instructions.

If the values are elevated, the person is referred to an endocrinologist. Further evaluation may include blood tests and imaging of the brain and kidneys.

Key point: cortisol changes throughout the day, so blood is taken in the morning and around 4 p.m., and the doctor may also suggest a urine or saliva test.

When to see a doctor

Symptoms of Cushing's syndrome are a reason for a visit — especially in those taking steroid medications. The doctor will ask about your complaints and, if necessary, order a check of cortisol in blood, urine, or saliva.

High cortisol by itself is not a reason to call an ambulance. The numbers 103 or 112 are needed if signs of a heart attack or stroke appear: with untreated Cushing's syndrome, such complications are among life-threatening conditions.

This material is for reference and does not replace a doctor's consultation: only a specialist can assess your situation and decide which examinations are needed.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer