The mechanism of the "fight or flight" reaction
Reaction to short stress. We see the robber's knife. The image of the knife goes to the part of the brain that checks everything for danger. This part is called the amygdala, and it triggers the fight-or-flight response.
From the amygdala, signals go through nerve fibers that put the body on alert. Such "exciting" fibers make up the sympathetic nervous system.
From the sympathetic nervous system, signals reach the adrenal glands, which release adrenaline and norepinephrine into the blood. They reach other organs through the blood and make them work for survival:
- The airways expand and allow more oxygen to flow into the blood.
- Heart muscles contract more often and pump blood faster.
- Blood-carrying arteries narrow and speed up the movement of blood.
- The liver produces glucose and releases it into the blood. So more glucose and oxygen feed the muscles for fighting or running.
- Pupils dilate and let in more light to see better.
- The rumor grows sharper.
- Goosebumps appear on the skin, which helps to retain heat in the body.
- Blood drains from organs unnecessary for running or fighting and flows to the muscles. It also casts off the skin so that it does not bleed when cut.
- The perception of pain decreases.
Reaction to prolonged stress. The stress response lasts longer if the danger has passed. For example, if a person lives in a criminal district. Then the main stress hormone, cortisol, which is also produced in the adrenal gland, begins to play a major role. In addition to mobilizing the body, cortisol suppresses functions that do not help to survive here and now - the digestive, immune and reproductive systems.
Stop stress. Stress ends when we notice that there is nothing to fear anymore. The withdrawal signal reaches the organs through "calming" nerve fibers - the parasympathetic nervous system.
When the fight-or-flight response hurts
The reaction mechanism arose in the process of evolution. In ancient times, it helped people escape from lions, leopards and other predators. And although the world has already changed, the reaction has remained. Now we prepare to hit or run because of thoughts about the upcoming exam or the mortgage payment. The body cannot change as fast as the world around it.
If the stress lasts for a short time, then there is nothing to worry about. It is much worse if the stress lasts for hours and days. The body is exhausted, diseases appear. Let's consider how some of them appear. Increased blood pressure. Constant stress requires constant efforts of the heart. The heart shakes the blood that sloshes through the arteries like water through a fire hose. To regulate this blood flow, the muscles around the arteries have to work harder. Because of this, muscles become overdeveloped and lose flexibility. Blood resistance in the arteries increases and blood flow accelerates even more. This is how chronically high blood pressure or hypertension appears.
Cardiac arrhythmia. Accelerated blood passes its circuit and returns to the heart. The heart copes with the blows of blood and grows muscles on the side from which the blood returns. Thus, one side of the heart becomes overdeveloped, there is a risk of cardiac arrhythmia6.
Depression. People stop following healthy habits due to stress. They get overworked and miss yoga or don't see friends. Irritability appears, which leads to quarrels in relationships, it is not possible to accurately analyze and refute depressive thoughts. All this can lead to depression.
Obesity. People often smooth out discomfort from stress with food. It brings relief and therefore becomes fixed in the behavior. Research shows that stress also affects food preferences: people choose high-calorie foods rich in harmful sugars and fats. Excess weight, in turn, causes problems with the joints of the legs, cardiovascular diseases, diabetes, etc.
Other problems. Stress worsens sleep, which makes headaches more frequent. Suppressed immunity deteriorates, and a person becomes susceptible to infections. There is an increased risk that plaques will appear in the arteries and a stroke or heart attack will occur. Men lose their erection.
How to stop the fight or flight response
Get support. Stress is reduced when we have support from friends. Social support groups are also effective for sharing feelings.
Relaxation techniques.
- Breathing exercises stimulate the vagus nerve, which stops stress. Such exercises do not require special skills and can be performed anywhere.
- Meditation. Although the stress response is physiological, it is the thoughts that cause it. These may be anxious thoughts about public speaking or an upcoming meeting. Meditation gets rid of them and brings the body to rest. Studies show that even 10 minutes of meditation is effective.
- Visualization techniques calm the body through imagination. They work because the brain responds to its imagination, which creates a calming and safe environment.
Physical exercises. Physical activity reduces stress hormones and produces endorphins, which create a sense of calm. Physical activity can include cycling, jogging, fitness, etc.
Main thoughts
The "fight or flight" reaction helps to save oneself. However, if the reaction lasts a long time, the body is exhausted and diseases appear. In order to avoid diseases, it is necessary to calm the body in time. Exercise, support from loved ones, and relaxation techniques help with this.
- Mriya.run: Space for Conscious Change. Learning, Practice & Tools
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- All about the fight or flight response

