- Physical Exercise -

Physical exercise is an important complement to dieting in securing weight loss. Aerobic exercise is also an important part of maintaining normal good health, especially the muscular strength of the heart. To be useful, aerobic exercise requires maintaining a target heart rate of 50 percent above one's resting heart rate for 30 minutes, at least 3 times a week.[citation needed] Brisk walking can accomplish this. For example, if the resting heart rate is 70 bpm (beats per minute), the target heart rate would be 105 bpm. Always consult a physician before beginning any exercise program, and ask what the appropriate target heart rate for your physical condition and age should be.

The ability of a few hours a week of exercise to contribute to weight loss can be somewhat overestimated. To illustrate, consider a 100-kilogram (220 lb) man who wants to lose 10 kilograms (22 lb) and assume that he eats just enough to maintain his weight (at rest), so that weight loss can only come from exercise. Those 10 kilograms (22 lb) converted to work are equivalent to about 350 megajoules (84,000 kilocalories). (We use an approximation of the standard 37 kilojoules or 9 kilocalories per gram of fat. Anyway, since the weight loss is also due to water loss, the actual loss will be slightly greater.) Now assume that his chosen exercise is stairclimbing and that he is 20 percent efficient at converting chemical energy into mechanical work (this is within measured ranges). To lose the weight, he must ascend 70 kilometers. A man of normal fitness (like him) will be tired after 500 meters of climbing (about 150 flights of stairs), so he needs to exercise every day for 140 days (to reach his target). However, exercise (both aerobic and anaerobic) would increase the Basal Metabolic Rate (BMR) for some time after the workout. This ensures more calorific loss than otherwise estimated.

The minimum safe dietary energy intake (without medical supervision) is 75 percent of that needed to maintain basal metabolism.[citation needed] For our hypothetical 100-kilogram man, that minimum is about 5,700 kilojoules (1,300 kilocalories) per day. By combining daily aerobic exercise with a weight-loss diet, he would be able to lose 10 kilograms in half the time (70 days).

There are also some easy ways for people to exercise, such as walking rather than driving, climbing stairs instead of taking elevators, doing more housework with fewer power tools, or parking their cars farther and walking to school or the office.

Source of Article: Wikipedia.org