Update: The October issue of Consumer Reports OnHealth magazine addressed 10 common myths about exercise. I will summarize these for today's column:
- Myth 1. Light exercise is not nearly as beneficial as strenuous exercise. While only strenuous exercise yields measurable increases in fitness, light exercise has been shown to have many advantages.First, moderate exercisers have almost the same decrease in death rates from coronary heart disease, cancer and all-cause mortality as those who work more intensely. In addition, non-strenuous exercise seems to reduce stress, anxiety and blood pressure as effectively as strenuous exercise does. And moderate exercise can be effective in weight control because calorie usage is related to total distance traveled, not how fast you travel it.
- Myth 2. You can lose fat from specific parts of the body by exercising those spots. There is no such thing as spot reduction. When you exercise, you use energy from all fat stores - not just those around the muscles doing the most work. In fact, your genes probably dictate which fat stores are used first and how fast any fat store gives up its fat. Strengthening the muscles can make you look thinner but will not help in spot reduction.
- Myth 3. Sports drinks can help you exercise more safely and effectively. The two main helpful ingredients in sports drinks are sodium, which helps the body retain water, and sugar, which the body burns for energy. However, few people work long or hard enough to benefit from these drinks. If you exercise less than an hour, the benefits of sports drinks are questionable.
Exercisers do need fluid. Try to drink two 8-ounce cups of water about two hours before a demanding workout, another cup every 20 minutes during the workout, and an additional cup or two within a half hour after the workout. For longer workouts or events, sports drinks may pay a real dividend.
- Myth 4. Aerobic exercise tends to make you hungry so it can actually undermine your efforts to lose weight. Aerobic exercise may indeed increase your appetite - but only if you need extra calories. Studies suggest that lean individuals do get hungrier after such exercise, to prevent them from getting too thin. In contrast, working out does not seem to boost appetite in obese individuals; so exercise should help them get slim.
- Myth 5. Strength training won't help you get thinner, since it burns few calories and adds pounds of muscle. Actually, strength training does substantially increase the number of calories you burn - about the same level as walking. Circuit training, where you move quickly from one station to the next, burns calories faster than walking does.
In one study, strength training boosted the average calorie-burning rate by 7 percent, burned off 4 pounds of fat and added nearly that much muscle. But, more important than the calories used during exercise are the calories used because you have a larger muscle mass. Another study found that women who ate a moderately restrictive diet and did either strength training or aerobic exercise lost more weight than those who only dieted. But those who split their workout time between strength training and aerobic exercise lost the most weight of all.
I'll do the remainder of these myths next week.