Stress hormones are chemical messengers that play a role in the body’s physiological and behavioral responses to stress. Examples include catecholamines and cortisol.

These hormones help initiate the adaptive “fight-or-flight” response to stress. However, chronic high levels of certain stress hormones can negatively impact a person’s physical and mental health.

This article explains what stress hormones are and how they affect the body. It also discusses the symptoms and potential consequences of high stress hormone levels.

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According to a 2017 review, stress hormones are signaling molecules that activate in response to a stressor. A stressor is an event that poses a real or perceived threat to a person’s well-being.

Stress hormones activate certain body systems in ways that allow a person to escape a threat. For example, they may increase heart rate and oxygen delivery to the muscles, helping a person escape danger.

Major stress hormones include cortisol and catecholamines. Cortisol is considered the primary stress hormone. Catecholamines are a group of hormones that include chemicals such as epinephrine and norepinephrine.

However, the term “stress hormone” is somewhat arbitrary, since no hormone is active only during stress.

For example, cortisol regulates the stress response and other functions, such as:

Likewise, the catecholamines epinephrine and norepinephrine play an important role in the following:

  • heart rate and blood pressure regulation
  • blood sugar regulation
  • metabolism
  • mood regulation
  • the sleep-wake cycle

Stress hormones allow the body to react to real or perceived threats. The body’s stress response consists of a fast and a slow response. Each of these responses can have different physiological and behavioral effects.

Fast response

The fast stress response involves activation of a system known as the sympathetic-adreno-medullar (SAM) axis.

When a stressor triggers the sympathetic nervous system, it causes a part of the brain called the medulla to release epinephrine and norepinephrine. These hormones act on special receptors in organs, muscles, and other tissues throughout the body to initiate the fight-or-flight response.

SAM axis activation has wide-ranging physiological effects that help with the fight or flight response. Examples include:

  • increased heart rate and blood flow to the skeletal muscles
  • increased oxygen consumption
  • increased sodium and glucose levels
  • enhanced arousal and alertness
  • focused attention
  • improved cognition

Slow response

The slow stress response involves activation of the hypothalamus-pituitary-adrenal (HPA) axis.

Here, a stressor triggers a part of the brain called the hypothalamus. The hypothalamus then releases a hormone called corticotropin-releasing-hormone (CRH) into the bloodstream, which acts on special receptors in the brain and body.

CRH works by stimulating the pituitary gland in the brain to release adrenocorticotrophin hormone into the bloodstream. This, in turn, stimulates the adrenal glands to release cortisol and other glucocorticoid hormones into the bloodstream.

According to the American Psychological Association (APA), cortisol can cause the following effects on the body:

  • increased blood glucose
  • increased glucose uptake in the brain
  • reduced inflammation

These effects can have short-term benefits. However, chronic low-level stress causes continued activation of the HPA axis, which can lead to health issues.

The fast and slow stress responses can each have different effects on the brain and body.

High catecholamine levels

Activation of the SAM axis temporarily increases levels of the hormones epinephrine and norepinephrine. These hormones can produce short-term physiological and behavioral effects, such as:

  • narrowing of the blood vessels
  • increased blood pressure
  • increased heart rate and cardiac output
  • increased blood flow to the skeletal muscles
  • widening of the airways in the lungs
  • increased oxygen consumption
  • increased sodium retention
  • increased glucose levels
  • reduced intestinal motility
  • pain relief or “analgesia”
  • enhanced arousal and alertness

High cortisol levels

Continued activation of the HPA axis can lead to high cortisol levels in the blood.

Certain health conditions can also cause high cortisol levels. As a result, the symptoms of high cortisol may vary depending on the cause. However, some general symptoms and complications of excess cortisol include:

Chronic stress dysregulates the HPA axis, leading to excess levels of cortisol and other stress hormones in the body.

Elevated stress hormone levels can disrupt almost all of the body’s functions. This can lead to certain physical and mental health issues.

According to the APA, chronic stress increases the risk of the following health problems:

The Centers for Disease Control and Prevention (CDC) notes that chronic stress can also cause people to engage in coping habits that increase their risk of disease. Examples include excess alcohol intake, smoking, and substance misuse.

A serum cortisol test measures levels of cortisol in the blood. Doctors may request this test if they suspect a person has a health condition involving very low or very high cortisol levels. This can include conditions such as Addison’s disease or Cushing’s disease.

Cortisol levels typically peak early in the morning and are at their lowest around midnight. Therefore, results may vary depending on the time of day and type of test.

Certain medical conditions can cause elevated stress hormone levels, which may require treatment.

However, stress hormones can also increase due to chronic stress. In such cases, managing the stress may help bring circulating stress hormone levels back within a typical range.

The CDC offers the following tips for dealing with stress:

A person should speak with a healthcare professional if they:

  • experience frequent episodes of acute stress
  • have been feeling stressed for a long time

People should also contact a doctor if they are using unhealthy coping mechanisms to deal with stress and want to find safer ways to manage their feelings.

A doctor can offer advice about treatment options. They can also refer someone to a mental health specialist, such as a psychiatrist or psychotherapist.

Stress hormones are chemical messengers that play a vital role in the body’s response to stress. They are also involved in other important body functions.

Stress hormones serve an adaptive purpose during times of acute stress. However, chronic stress can cause persistent high levels of cortisol. This can lead to complications, such as high blood pressure and diabetes.

A person should speak with a healthcare professional if stress becomes chronic or causes other mental and physical symptoms. Healthcare professionals can offer treatment options and management strategies to lower stress hormone levels.