General adaptation syndrome (GAS) is a three-stage response that the body has to stress. Possible causes include psychological stress and life events.

Stress is sometimes thought of as a mental pressure, but it also has a physical effect on the body. Understanding the stages the body goes through when exposed to stress helps people become more aware of these physical signs of stress when they occur.

This article explores what general adaption syndrome (GAS) is, its different stages, and when it may occur. It also considers how people can better manage their response to stress.

Fast facts about GAS:

  • GAS is a three-stage process that the body goes through when it is exposed to stress.
  • It is vital to find ways to manage it to limit the effects on the body.
  • Causes of the process include life events and psychological stress.
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GAS describes the way the body responds to stress.

Hans Selye, a Vienna-born scientist, working in the 20th century, was the first person to describe GAS.

Selye found that rats displayed a similar set of physical responses to several different stressors. The latter included cold temperatures, excessive physical exertions, and injection with toxins.

The scientist explained GAS as the body’s way of adapting to a perceived threat to better equip it to survive. A paper on Selye’s GAS theory was published in The Journal of Clinical Endocrinology in 1946.

The three stages of GAS are:

  • alarm reaction
  • resistance
  • exhaustion

What happens within the body during each of these stages is explored below.

Alarm reaction stage

At the alarm reaction stage, a distress signal is sent to a part of the brain called the hypothalamus. The hypothalamus enables the release of hormones called glucocorticoids.

Glucocorticoids trigger the release of adrenaline and cortisol, which is a stress hormone. The adrenaline gives a person a boost of energy. Their heart rate increases and their blood pressure rises. Meanwhile, blood sugar levels also go up.

These physiological changes are governed by a part of a person’s autonomic nervous system (ANS) called the sympathetic branch.

The alarm reaction stage of the GAS prepares a person to respond to the stressor they are experiencing. This is often known as a “fight or flight” response.


During the resistance stage, the body tries to counteract the physiological changes that happened during the alarm reaction stage. The resistance stage is governed by a part of the ANS called the parasympathetic.

The parasympathetic branch of the ANS tries to return the body to normal by reducing the amount of cortisol produced. The heart rate and blood pressure begin to return to normal.

If the stressful situation comes to an end, during the resistance stage, the body will then return to normal.

However, if the stressor remains, the body will stay in a state of alert, and stress hormones continue to be produced.

This physical response can lead to a person struggling to concentrate and becoming irritable.

Exhaustion stage

After an extended period of stress, the body goes into the final stage of GAS, known as the exhaustion stage. At this stage, the body has depleted its energy resources by continually trying but failing to recover from the initial alarm reaction stage.

Once it reaches the exhaustion stage, a person’s body is no longer equipped to fight stress. They may experience:

If a person does not find ways to manage stress levels at this stage, they are at risk of developing stress-related health conditions.

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Stressful life events and experiences, such as being in debt or having problems at work, may lead to GAS.

Selye’s study was limited to physical stressors, such as cold temperatures and physical over-exertion. However, it is now understood that life events that induce psychological stress cause the same physical reactions, as were seen in Selye’s study.

The sort of life events that can cause a person to experience stress and GAS include:

  • relationship breakdowns
  • losing a job
  • medical problems
  • money troubles

In theory, the fact that these situations can cause GAS may be beneficial. The alarm reaction gives people a burst of energy and concentration that could help them to problem-solve.

For most people, however, the physical response their body goes through when they are under stress is not helpful.

Unlike threats people may have faced in the Stone Age, a person nowadays is unlikely to be able to resolve a stressful situation of modern-day life with a burst of energy.

Long-term stress can have a negative impact on a person physically and on their immune system. A 2008 paper noted that chronic stress could:

A review from 2008 further explains that chronic stress is also linked to an increased risk of heart disease.

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Writing a journal and practicing mindfulness may help to treat GAS.

The first step to controlling GAS is to understand what triggers stress.

Different things trigger stress for different people. It is important for a person to identify what situations and events are particularly stressful for them. It may then be possible to make lifestyle changes to reduce exposure to these triggers.

For example, a long commute may be stressful. If so, moving job roles somewhere closer to home, or asking to work remotely, may help.

When it is not possible to avoid a stress trigger, it is important to find a way to reduce the impact it has on body and mind.

The Anxiety and Depression Association of America recommend physical activity as a way of reducing stress. Exercise releases endorphins, which improve sleep and promote a sense of wellbeing. Brisk walking or running are easy ways to take exercise.

The following activities may also help:

  • mindfulness and meditation
  • deep breathing
  • yoga and tai chi
  • relaxing baths
  • journaling
  • seeing friends to talk issues through

Stress causes physical changes in the body. GAS is a three-stage process the body goes through when exposed to stressful events. Long-term stress has a negative impact on physical and mental wellbeing.

The final physical stage of GAS is known as exhaustion and may happen when a person is exposed to stress for extended periods of time. This, in turn, makes them more vulnerable to stress-related illness.

Understanding stress triggers may help someone to make lifestyle changes to reduce stress.

Where this is not possible, finding ways to manage the impact of stress on the body and mind is critical.

Managing stress can include activities, such as deep-breathing, yoga, mindfulness, or meditation.