Numerous surveys confirm that adult Americans perceive they are under much more stress than a decade or two ago. A 1996 Prevention magazine survey found that almost 75% feel they have "great stress" one day a week with one out of three indicating they feel this way more than twice a week. In the same 1983 survey only 55% said they felt under great stress on a weekly basis. It has been estimated that 75 - 90 percent of all visits to primary care physicians are for stress related problems.

The body's response to stress is somewhat like a jet getting ready for take-off. Almost all systems (the immune system, the lungs, the blood vessels and heart, the digestive system, the sensory organs, and brain) are modified to meet the perceived danger.

External and Internal Stressors

People can experience either external or internal stressors.

  • External stressors include adverse physical conditions (such as pain or hot or cold temperatures) or stressful psychological environments (such as poor working conditions or abusive relationships). Humans, like animals, can experience external stressors.
  • Internal stressors can also be physical (infections, inflammation) or psychological. An example of an internal psychological stressor is intense worry about a harmful event that may or may not occur. As far as anyone can tell, internal psychological stressors are rare or absent in most animals except humans.

Acute or Chronic Stress

Stress can be short-term (acute) or long-term (chronic). Acute stress is a reaction to an immediate threat or perceived threat.

Acute stress is the reaction to an immediate threat, commonly known as the fight or flight response. The threat can be any situation that is experienced, even subconsciously or falsely, as a danger. First the stress hormone adrenaline is released. Then the heart beats faster, breath quickens and blood pressure rises. The liver increases its output of blood sugar, and blood flow is diverted to the brain and large muscles. The body triggers the production and release of steroid hormones including cortisol, which is very important to the function of the heart, lungs, circulation, metabolism, immune systems, and skin when a stressor is present.

Acute Stressors

  • noise, crowding, isolation, hunger, danger, infection, imagining a threat, remembering a dangerous event

Under most circumstances, once the acute threat has passed, the response becomes inactivated and levels of stress hormones return to normal, a condition called the relaxation response. Frequently, however, modern life poses on-going stressful situations that are not short-lived and the urge to act (to fight or to flee) must be suppressed. Stress, then, becomes chronic.

Chronic Stressors

  • on-going highly pressured work, long-term relationship problem, loneliness, persistent financial worries

Remember that the word stress is often used to refer to outside events, when actually; stress is not the event itself, but our response to it. This is why it is important to understand how stress affects us and how to deal with it.