Cortisol

What is Cortisol?

Cortisol is a steroid hormone produced by the adrenal glands, located on top of the kidneys. It contributes to the body’s stress response and is often called the “stress hormone.” Cortisol has a wide range of physiological effects, including regulating metabolism, immune function, and blood pressure, as well as influencing mood, memory, and learning.

Functions and Effects of Cortisol

• Stress Response

  Cortisol is released in response to stress, whether it be physical, emotional, or psychological. Cortisol helps mobilize energy during the HPA-axis stress response. It works alongside faster autonomic responses and also has important daily functions independent of an immediate threat.

• Metabolism and Energy Regulation

  Cortisol plays a key role in regulating the body's metabolism. It promotes the breakdown of proteins and fats to provide energy, helps maintain blood sugar levels, and assists in the regulation of insulin production. Cortisol's actions help ensure that the body has sufficient energy resources to cope with various challenges and maintain homeostasis.

• Immune Function

  Cortisol also has anti-inflammatory and immunosuppressive effects. It helps modulate the immune system, preventing excessive inflammation and tissue damage. However, prolonged exposure to high levels of cortisol can weaken the immune system and increase the risk of infections.

Cortisol in Neuroscience Research

• Impact on Mood and Cognition

  Research has demonstrated that cortisol can impact mood, memory, and cognition. Elevated cortisol levels have been linked to anxiety, depression, and impaired cognitive function, particularly in areas related to learning and memory. Chronic stress and glucocorticoid exposure can affect brain plasticity, but effects vary with duration, context and individual factors.

• Psychological Stress and Health

  Research on cortisol has contributed to our understanding of the link between psychological stress and physical health. Prolonged exposure to stress and elevated cortisol levels have been associated with a range of health problems, including obesity, diabetes, cardiovascular disease, and impaired immune function. Studies of stress-management approaches may measure cortisol, but a change in that measure does not by itself establish better health or explain why an intervention helped.

• Measuring Cortisol Levels

  Various methods are used to measure cortisol levels, including blood, saliva, and urine tests. Interpretation depends on the specimen, sampling time, medication use and clinical question. Cortisol varies across the day, so a single value is not a general score of psychological stress or overall health. In research settings, cortisol measurements are often used to assess the impact of stressors on participants and to investigate the relationships between stress, cortisol, and various aspects of cognitive and emotional functioning.

Sources and evidence

• Herman and colleagues: Regulation of the Hypothalamic-Pituitary-Adrenocortical Stress Response. Stress responses can be adaptive or maladaptive depending on context.
• MedlinePlus: Cortisol blood test.