It's a beautiful day in Yellowstone National Park. You emerge from your tent into the morning sunlight, a gentle breeze delighting your senses. As you prepare breakfast over the camp stove, you notice a movement out of the corner of your eye. It's a bear! Your heart starts to pound, your blood pressure goes up, your breath accelerates, and your digestion turns down. This is the normal and appropriate physiological response of your body dispensing the stress hormones you need to prepare the body to "fight-or flight."

This well-documented biological event is the response shared by humans and animals and is extremely helpful when the individual faces physical danger. If the problem can be solved by "fighting," taking action to scare the bear away, or by "flight," running away so fast the bear can't harm you, the solution itself dissipates the stress and bodily functions return to normal. When stress is caused by a problem, situation, or condition that can't be solved through such a response, the impact extends for a longer period and upsets the Triad of Health.

When the body is physically, chemically, or emotionally overloaded, it causes a state of alarm that sets off a complex interaction called the stress cycle. Research scientist and medical doctor Hans Selye introduced the concept of stress in the 1930s. He showed that a variety of chemical changes accompany stress and proved that a stress reaction results from excess physical, chemical, or emotional pressure.

Selye also delineated the four phases of stress:

1. Alarm

2. Adaptation

3. Fatigue/exhaustion

4. Death

The alarm stage starts when the brain activates the sympathetic nervous system to stimulate the adrenal glands to release norepinephrine and adrenaline. Cortisol is also secreted from the adrenals. One of its functions is to stimulate the breakdown of glycogen into glucose, which is sugar, to be used for energy.

When the same stress is repeated frequently, our bodies adapt and respond less intensely. However, this adaptation lowers our tolerance for new stress. So, we may adapt to caffeine, sugar, alcohol and nicotine, yet then we become less able to tolerate emotional or physical stress. We become so desensitized to stress that symptoms become chronic and are taken as normal. For example, stomach bloating, gas and hiccups are all symptoms of not digesting properly, yet we are led to believe by advertisements that this is not unusual, actually it is common and that simply taking an antacid will take care of it. This does not address the cause, but simply masks the symptom. However, one can never treat enough symptoms to correct the cause.

Repeated adaptation leads to the third phase of stress - fatigue and exhaustion. Here the autonomic nervous system comes into play. The autonomic nervous system has two parts:

1. The parasympathetic nervous system ' the part that heals us when we rest.

2. The sympathetic nervous system ' the "fight-or-flight" reaction - when this system is under attack from a stressor, it turns down the immune system and increases the chances of getting diseases. Lowered resistance invites disease.

Selye discovered and documented that stress differs from other physical responses in that stress is stressful whether one receives good or bad news, whether the impulse is positive or negative. Thus, it is not the event itself, but our reaction to the stress that harms us.