Myths of Aerobic Exercise and Weight Control

Among the more popularly help myths and misconceptions concerning the relationship between aerobic exercise and weight control are the following:

Myth: Aerobic exercise is all the exercise you need to effectively control your weight.

Fact: A review of the available data strongly indicates that, in general, combining a conventional aerobic exercise program with a calorically restricted diet does little to help you preserve lean body mass during your weight-reduction efforts. It is important to keep in mind that the lower your lean body mass is, the lower your resting metabolic rate ( the calories expended by the body to maintain life and normal bodily functions such as respiration and circulation) will be. As a result, it is more likely that you will regain some or all the weight you lost. ON the other hand, if you engage in an exercise program that is designed to improve your level of muscular fitness and weight loss, you enhance the likelihood that you will be able to maintain your level of lean body mass. Accordingly, the optimal exercise prescription for sound weight management is one that combines aerobic conditioning and strength training. Such prescription, will allow you to expend a relatively large number of calories, while simultaneously preserving or increasing your level of lean body mass.

Myth: Aerobic exercise causes your resting metabolic rate to stay elevated for an extended period of time after a workout.

Fact: In general, the available scientific data indicate that the amount of energy expended after an aerobic workout tends to be very small. The number of calories burned during recovery depends upon the intensity and the duration of the workout. Following exercise of unusual intensity and duration, your metabolic rate may remain elevated for as long as 24 hours, but at a point that is just barely above your resting metabolic baseline level. In general, approximately 15 extra calories are burned during recovery for every 100 calories you expended during your exercise bout.

Myth: The more you sweat during exercise, the more fat you lose.

Fact: If you exercise in extreme heat or humidity or in “rubberized” clothing, you certainly will sweat profusely and lose weight. Any resultant weight loss, however, represents only lost water, not lost fat. When you replenish your body fluid stores by eating and drinking, those lost pounds return almost as the left. Another problem with attempting to lose weight through “sweating it off” is heat injury/ Heat injury can occur if you exercise too vigorously in extreme heat or in rubberized clothing, both of which preclude you from safely controlling your core temperature by preventing your sweat from evaporating. Keep in mind that how much you sweat is not a good barometer of how much energy you are expending. Perspiring is more dependent on such factors as temperature, humidity, lack of conditioning, body composition and individual variability.

Myth: You can burn fat from specific regions of the body by exercising those areas.

Fact: Contrary to what anyone may want you to believe, the phenomenon of spot reduction has absolutely no factual basis. When you exercise, you utilize energy produced by metabolizing fat from all the regions of your body, not just the specific muscles involved in the exercise. Performing sit-ups, for example, will not trim the fat off your abdominal region any more rapidly than off your back or thighs. The exercise may firm up the area but will not make it disappear.

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