Cortisol level: what it is, the norm, causes of deviations and diagnosis

Cortisol is one of the most important hormones in the human body, produced by the adrenal glands in response to stress. It affects metabolism, the immune system, blood pressure, and blood glucose levels. Abnormalities in cortisol levels can be associated with both physiological factors and serious diseases.

What is cortisol and why is it needed?

Cortisol is a hormone that belongs to the glucocorticoid group. Its secretion is controlled by the hypothalamic-pituitary-adrenal axis:

1. The hypothalamus secretes corticoliberin, which stimulates the pituitary gland.
2. The pituitary gland produces adrenocorticotropic hormone (ACTH), which activates the adrenal glands.
3. The adrenal glands produce cortisol, which enters the bloodstream and acts on various organs and systems.

The main functions of cortisol:

• Metabolic regulation – maintains glucose levels, promotes the breakdown of fats and proteins.
• Impact on the immune system – has anti-inflammatory and immunosuppressive effects.
• Blood pressure control – helps regulate water-salt balance and vascular tone.
• Adaptation to stress – mobilizes the body's resources in difficult situations.

Cortisol levels in the blood

Cortisol levels vary throughout the day: the highest level is observed in the morning and the lowest in the evening.

Causes of elevated cortisol

Increased cortisol levels can be temporary (physiological) or persistent (pathological).

Physiological causes

• Chronic or acute stress
• Intense physical activity
• Pregnancy
• Sleep deprivation
• Hunger or unbalanced diet

Pathological causes

• Cushing's syndrome – hyperproduction of cortisol by the adrenal glands or due to a pituitary tumor.
• Adrenocorticotropic pituitary tumor – promotes excessive production of ACTH, which stimulates cortisol.
• Long-term use of glucocorticoids – used for autoimmune diseases and inflammatory processes.
• Chronic liver disease – impaired cortisol metabolism.
• Adiposity – helps increase hormone levels due to metabolic disorders.

Symptoms of high cortisol:

• increased appetite and weight gain (especially in the abdominal area)
• increased blood pressure
• insomnia and anxiety
• weakening of immunity
• thinning of the skin, bruising
• menstrual cycle disorders in women

Causes of low cortisol

A decrease in cortisol levels may be associated with disorders in the adrenal glands or pituitary gland.

Physiological causes

• Reducing stress
• Transition to a balanced diet and rest regimen

Pathological causes

• Addison's disease – adrenal insufficiency.
• Pituitary insufficiency – reduced ACTH production, which affects cortisol production.
• Adrenal insufficiency after long-term steroid use – the body stops producing its own cortisol.
• Genetic disorders – some congenital syndromes may be accompanied by cortisol deficiency.

Symptoms of low cortisol:

• chronic fatigue and weakness
• weight loss
• low blood pressure
• hypoglycemia (low blood glucose)
• increased skin pigmentation (with Addison's disease)

How to determine cortisol levels

Diagnosis of cortisol levels includes laboratory tests and additional examinations to determine the causes of deviations.

Laboratory tests

1. Cortisol blood test – is performed in the morning or evening, as hormone levels change throughout the day.
2. Urine analysis for free cortisol – helps to estimate daily hormone production.
3. Saliva analysis for cortisol – used to assess the circadian rhythm of cortisol.

Additional diagnostic methods

• Dexamethasone test – helps determine the causes of elevated cortisol.
• ACTH analysis – assessment of the regulation of adrenal function by the pituitary gland.
• MRI of the pituitary gland or CT of the adrenal glands – used when tumors or endocrine system dysfunction are suspected.

Cortisol levels are an important indicator of health. They affect metabolism, immunity, and the body's energy balance. Regular monitoring of this hormone helps to detect abnormalities in time and maintain the body in a harmonious state.