University of Connecticut University of UC Title Fallback Connecticut

Physiology of Stress

Fight or Flight

When a person is faced with a perceived threat the body prepares for two modes of action: fight and attack or run away from the danger. The fight or flight response is thought to have helped humans against life threatening situations. As humans have evolved it is theorized that the fight or flight response has not developed at the same pace as the brain.

Example of Fight or Flight Response:

  • Sensors perceive the stimuli (Example: witnessing a car accident)
  • Brain deciphers the information as either a threat or non-threat
  • If a threat, the body activates the nervous and endocrine systems to a fight or flight response
  • The response is continued until the threat is gone or over
  • When the threat is gone, the body returns to state of calmness

The Physiology of Stress: What Happens to the Body

  • When the fight or flight response is activated, adrenaline is released. This switches on the alert button and the person becomes more energetic
  • Increase in heart rate and breathing
  • Blood used for digestion is sent to muscles
  • If it is an acute response, the body quickly recovers
  • If the stress is chronic, the body does not return to its normal status and this result can cause wear on the body
  • Chronic stress can cause:
    • Insomnia
    • Backaches
    • Tension Headaches
    • Migraine Headaches
    • Ulcers and Colitis
    • Temporomandibular Joint (TMJ) Syndrome
    • High Blood Pressure
    • Coronary Heart Disease

 Seek help when necessary

If someone is under more stress than just dealing with a passing difficulty, it may be helpful to talk with a medical professional, spiritual advisor, counseling and mental health staff, or employee assistance professional.