How does your body respond to a stressful situation / Physiology of stress
Stress is a situation which demands action by our body. Every individual has a normal resistance to stressful events. While some can tolerate high levels of stress and others much less, every individual has a threshold at which stress starts affecting the mind and body adversely. Our body reacts to a stressor through physiological changes called the General Adaptation Syndrome (GAS). The GAS can pass through three stages depending on how long the stressor continues.
Stage 1 (Alarm reaction): This is our body’s first response to a stressor which is characterized by :
- Increased blood pressure
- Increased heart rate
- Increased blood flow
- Increased voluntary muscle tension
- Increased perspiration
- Increased frequency of breathing
- Decrease in routine body functions like digestion
The objective is to prepare the body for a vigorous physical response by diverting energy to body systems / parts which will perform the physical activity (in simple words we can say the body is in the stress handling mode – fight or flight response). The identifiable symptoms of this reaction are :
- Dryness of mouth
- Body ache
- Cold hands and feet
If the stressor is transitory, the body returns to normal the moment the stressful situation is over. The problem arises if the stressor is prolonged and chronic. The body constantly remains in the stress handling mode. In such cases, the GAS proceeds to the second phase…
Stage 2 (Resistance stage): The physiological changes which began during the alarm reaction continue for a longer duration (as long as the stressor is present) and is accompanied by the release of stress hormones (hormones are chemicals released directly into the blood stream by special glands called endocrine glands to be transported around the body so they can have a specified effect on a particular organ).
- The brain and pituitary gland respond to stress by releasing Adreno Cortico Trophic Hormone (ACTH).
- ACTH stimulates the adrenal glands to increase the production of hormone like catecholamines (epinephrine, norepinephrine) and cortisol.
- These hormones stimulate the heart, increase blood pressure, blood glucose levels and heart rate, constrict blood vessels for increased blood flow to muscles and brain and decrease blood flow to the digestive tract and internal organs.
Prolonged high levels of these hormones are harmful and can lead to disorders like heart and blood vessel disease. There is a reduction in the body’s immunity and therefore a person becomes more susceptible to infections. The longer the resistance stage the more damaging it is.
Stage 3 (Exhaustion stage): Prolonged exposure to a stressor without resolution may lead to the exhaustion stage. The person reaches a state of breakdown and can no longer fight the stressor. This stage is characterized by continuous headache, ulcers and high blood pressure. A person passing through this stage needs immediate medical attention and professional counseling.