General Adaptation Syndrome: Stages, Definition & Examples

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  • 0:02 General Adaptation…
  • 0:45 Stages of GAS
  • 2:29 Example of General…
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Lesson Transcript
Instructor: Peggy Olsen
General adaptation syndrome (GAS) is the predictable way the body responds to stress as described by Hans Selye (1907-1982). Learn more about the three stages of general adaptation syndrome and test your knowledge with quiz questions.

General Adaptation Syndrome Defined

Think about a time you were stressed. What did it feel like? How did you know you were stressed? You probably remember your heart rate increasing. If you were stressed long enough, you may have felt tired and even gotten sick. Hans Selye described three predictable stages the body uses to respond to stressors, called general adaptation syndrome (GAS). The first stage is the alarm stage, which provides a burst of energy. In the second stage, known as the resistance stage, the body attempts to resist or adapt to the stressor. The last stage is known as the exhaustion stage because energy is depleted.

Stages of General Adaptation Syndrome

During the alarm stage, the body responds to the distress signal sent to the hypothalamus with a burst of energy to help deal with the stressor. If you were walking at night and something jumped out from behind a tree, your hypothalamus would tell the pituitary gland to release glucocorticoids, which are hormones. In response, the adrenal glands release cortisol and adrenaline to help the body react. In addition to an increase in heart rate and breathing rate, blood glucose levels increase to boost energy.

Once your body initially responded to the stress of whatever jumped out from behind the tree, it will continue to maintain a level or alertness to help fight or adapt to the stressor. This is called the resistance stage. The adrenal cortex continues to release glucocorticoids to help the body react to the stressor until the stress is resolved or the body can no longer resist. Deep energy reserves are used until the stressor is resolved or reserves are depleted. Because the body's energies are going to the stressor, the body is not able to fight off colds and flu during this time.

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