Several readers have asked how to start a running program. With the many fitness fads that have swept the nation in recent years, it seems that walking has been disregarded as a valuable exercise. Regular exercise will increase your energy, improve your mental health and help you toward a more positive outlook.

Walking (later to jogging and then to running), is the most natural exercise known to man. It requires no special training, no particular terrain and no outlay of money. A brisk 30-minute walk is considered to be an aerobic exercise, meaning that as you walk, you are increasing your body's ability to utilize oxygen. At the same time, walking gently elevates the heart rate, therefore increasing the heart's efficiency as a pump and improving the body's metabolism for the future running program and good cardiovascular stimulation. As one progresses from a walking program into a more active program such as jogging, it is helpful to know certain guidelines.

The speed at which you jog is not the important factor -- it is the distance. If you weigh 150 lbs and force that weight through a distance of one mile, you will use about 60 calories more energy than you would sitting still for the same period of time. It doesn't matter whether you walk the mile or jog or do it in one hour or in 10 minutes; the force through distance equation will be the same. The most important factor in the use of exercise to help control body fat is to concentrate on the distance you can travel, not how fast you can go.

Losing weight by exercise is slower than by severe calorie restriction, but it is more effective. If you were an athlete when you were younger, you will have no problem in jogging. If you were not an athlete, your own natural instincts providing just the right personal exercise form will come into action. Jogging is a simple type of exercise requiring no highly developed skills. It should be remembered that age plays no role. You can be an athlete at any age. Once you get your jogging program in place and are comfortable, a running program may be where you go from there.

Dr. Robert F. Weiss is a Fairfield native and practices podiatry in Darien. He was a member of the Medical Advisory Committee of the 1984 and the 1988 Olympic Trials.