A、because they actually do harm to his or her health B、because they only stimulate his or her imagination C、because they increas

Woman: It would be difficult for many people to do file amount of exercise you prescribe. What about a softer schedule? Is it worthwhile, for example, to jog for l0 or 15 minutes instead of 30 mutes?
Man: Any exercise is worthwhile. Some people are in such bad physical shape that it might take them years to work up to the levels I suggest. My recommendation would be to start at a level you can maintain and try to increase it. One way a weekend exercise can measure whether he or she is training the heart is to check how rapidiy file pulse rate drops after a workout. If file rate begins to drop more quickly, that is a good sign.
Woman: What should a person do to guard against the dangers of over-exercising?
Man: The single most important thing is not to exercise at an intensity greater than your heart can stand. And this can usually be determined by a stress electrocardiogram. You should also allow your body a proper recovery period after vigorous exercise, This recovery period will depend on your condition and your sport. Runners, for example, usually allow them selves a 48-hour recovery period between hard hms. So if you were to go out and nm hard for 4 or 5 miles, the next day you should nm at a more relaxed pace. Swimmers don’t need as long a recovery period--perhaps 24 hours. But there are people who might require a five- or six-day recovery period.
Woman: What are the wanting signs that you are overdoing it with your exercising?
Man: The three most dangerous signs are chest pains during exercise, or heart palpitations--a sudden fast heartbeat--when you’ re idle, and unexplained dizzineas. If you feel such symptoms, you should stop your exercising and check with your physician.
Woman: Does exercise help much in taking off weight?
Man: Definitely. Exercise bums calories. But it also goes beyond that. When you exercise, food passes through your intestinal tract much faster, and as a result you absorb a decreased percentage of your food. For example, a meal passes through an average person in about 24 hours. But marathon numbers have a food transit time of 4 to 6 hours. Even after you stop exercising, your body continues to bum increased calories for 5 or 6 hours a day--and tests show that can account for a 5-to-10-pound weight loss in a year. Another way exercise helps is that it curbs hunger. When you exercise, fat is re]eased into your blood-stream and your blood-sugar level doesn’t drop. And low blood sugar is the single most important stimulus to make you hungry. So when people exercise, they are likely to eat less.
Woman: Isn’t diet important in losing weight?
Man: Of course. But if you don’t exercise, 25 to 50 percent of the weight you lose will be muscle. So if you ever get back up to your previous weight, you will really be fatter than before you started dieting. Even if you lose weight by dieting alone, studies show you are not likely to keep the weight off.
Woman: Is diet important to exercises? Should one eat certain foods and avoid others?
Man: The rules for healthful diets for exercisers are the same as for nonexercisers. Nearly all Americans eat too much sugar, too much salt and too much animal fat. The average American eats too much meat, and it’s fat that enhances file flavor of the meat. And animal fat is unquestionably associated with increased susceptibility to heart attacks.
Woman: How about daffy products?
Man: Dairy products are an excellent source of carbohydrates, fats and protein. All the protein you need can be supplied by milk. The warning is that you don’t need all that fat in milk. You may solve that by drinking skim milk or powdered milk.
Woman: Should one take more vitamins when exercising?
Man: They are excellent after-exercise drinks. So is beer. But during competition, the ideal drink is water.
Woman: Can drugs such as amphetamines increase an athlete’s performance?
Man: Tire evidence indicates that amphetamines don’t actually improve your performance. They just make you think you’re performing better than you are--make you think you can do things you re ally can’t do. A football halfback, for example, will think he can knock over a 350-pound tackle instead of hunting for a hole in the line.
Woman: Dr. Mirkin, you’ ve exploded quite a few myths in this interview, haven’t you?