How Stress Affects Your Health and Your Body

David Yarian Ph.D.

The Stress Response Affects All Systems in the Body

Medical researchers have traced the stress response as it cascades throughout the body, affecting every system of the body. When the brain perceives threat or danger, the hypothalamus sends a signal to the pituitary gland, which releases adrenocorticotropic hormone (ACTH) which in turn signals the adrenal glands to spill cortisol, adrenaline and noradrenaline into the bloodstream. These are the so-called stress hormones, which have a powerful impact on the body, mobilizing it for fight or flight.

What Happens in the Body Systems with the Stress Response

The Harvard Medical School Special Health Report on Stress Control summarizes what happens next:

Your breath quickens as your body takes in extra oxygen. Energy-boosting glucose and fats are released from storage sites into your bloodstream. Sharpened senses, such as sight and hearing, make you more alert.

Your heart beats faster - up to five times as quickly as normal - and your blood pressure rises. Certain blood vessels constrict, which helps direct blood flow to your muscles and brain and away from your skin and other organs.

Blood cells called platelets become stickier so clots can form more easily to keep you from bleeding to death from potential injuries. Immune system activity picks up. Your muscles - even tiny, hair-raising muscles beneath your skin - tighten, preparing you to spring into action.

Body systems not needed for the immediate emergency are suppressed. The stomach and intestines cease operations. Sexual arousal is quashed. Repair and growth of body tissues and bones halt.

All of this is exactly we need -- to hunt a mastodon or saber- toothed tiger, to fight an enemy, or to flee for our lives from a real and immediate danger.

Ready for Action in a Threatening Situation

In the early 70's I was threatened at midnight by a mugger with a knife in the East Village of New York City. I ran from him, many blocks to a subway station where there were lights and people. I ran faster than I knew was possible, thanks to the stress response which mobilized my body for flight.

Chronic Stress Response Is a Problem

Problems arise in modern life, however, where these physiological responses may be triggered fifty or more times a day in reaction to anxiety or stress-inducing situations, such as an exam or a fender-bender or an interaction with a difficult person. Normal life events, both positive and negative, may also induce a chronic stress response, lasting long after the stressful event has passed.

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