Stress is such a part of our culture that somebody could call worrying the national pastime. Medications for stress-related diseases are indeed available (and, in some cases, required), but there are other, more natural ways to avoid becoming a stress statistic - exercise and laughter.

If they seem like an odd couple, you should know that both exercise and laughter stimulate the body's release of morphine-like derivatives known as endorphins, thus making a person feel good and alleviating the stress accumulated during a typical day.And make no mistake - stress affects the body dramatically. When a person faces a stressful situation, the heart beats faster, the blood pressure rises and the breathing rate increases. A person feels flushed and muscles tense, preparing for action. This is the body's way of preparing for two survival mechanisms - fight or flight.

This response is tremendously helpful in dealing with short-term physical stresses, such as encountering an animal in the forest. It's fine for people who have to draw their daily sustenance from the woods, but in an industrialized society, the fight-or-flight response may not be such a boon.

In fact, if all of our stresses were as obvious as a wild animal threatening to charge - or, to draw a more likely example from modern life, a mean dog on the street - we could probably deal with them more effectively. After all, it's hard to get a vicious dog to wait around while a person thinks about how to respond.

But anticipating a speech at work or wondering about paying the mortgage are much more subtle stresses. Because they are so much more remote, we are much less likely to deal with them immediately, and thus we add to the stress we face during a normal day. The problem here is that prolonged stress increases levels of fatty acids in the bloodstream, decreases the body's immune response, and increases the risk of hypertension, heart disease and even the common cold.

Several clinical studies indicate that exercise not only improves mood, but also instills a sense of well-being. Other research has shown that exercise as mild as a 15-minute walk can be far more relaxing than a tranquilizer. So think of exercise as a workout for the body and a holiday for the mind, and start getting some regularly. But don't assume that the more a person exercises, the less stress there will be.

For one thing, overdoing any exercise program at the beginning could lead to getting hurt or burning out. For another, consider catecholamines. They are chemicals produced by the adrenal gland, and they increase the risk of heart disease, hypertension and ulcers.

Strangely enough, while moderate exercise increases the metabolism and uses the excess catecholamines that result from stress, intense exercise actually prompts the release of more catecholamines. As always, check with a physician before beginning to exercise, especially if you've been relatively inactive or if you have a family history of heart disease.

Laughing is another great way to diminish stress. There is hardly a system in the body that isn't stimulated every time a person enjoys a hearty laugh. The chest, abdominal muscles, diaphragm, heart and lungs contract, and the muscles in the cheeks get a workout, too. A real belly laugh can push systolic blood pressure from an average 120 to a temporarily hypertensive 200, and can double the pulse rate from 60 beats per minute to 120.