Getting Americans off the couch and onto their feet could save an estimated 200,000 lives a year. Yet most of us are either sedentary or only minimally active.
Exercise myths may keep many couch potatoes from getting into shape.
People still ask questions like: How often should I exercise? (The more, the better, but at least 30 minutes nearly every day.) Does it have to be 30 minutes straight? (No, shorter bouts are fine.)
Do I need to go to the gym? (No, walking, dancing, lawn mowing, and gardening are fine, if they’re intense enough.) Still, in a world where infomercials, magazines, videos, and friends may give conflicting advice, misunderstanding abounds. Let’s clear up some common exercise myths.
1. Strength training will make women too muscular
The first of the exercise myths to tackle is about strength-training. “Many women are afraid that strength-training will make them bulky,” says Miriam Nelson of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston. “They think strength-training is only for men.”
In fact, strength-training has enormous benefits for women. In one of Nelson’s studies, postmenopausal women who were sedentary were randomly assigned to do strength-training exercises twice a week or to do no additional exercise. After a year, the strength-trainers had greater bone density, muscle mass, muscle strength, and balance than the sedentary women.
2. Light weights on your arms or legs can boost your exercise benefit
The second of the exercise myths doesn’t hold much weight. Some people carry light (one- or two-pound) hand-held weights when they walk or run. Others strap velcro-fastened weights around their ankles. Don’t bother, says exercise physiologist Ben Hurley of the University of Maryland.
“It slows you down, so you get less benefit from aerobic exercise, and it doesn’t add enough weight to give you the benefits of strength-training,” he explains.
To build muscle, you have to use weights that you can lift no more than eight to 12 times in a row. “If you can go beyond the twelfth repetition, the resistance is too light to stress the muscle,” says Hurley. “As your muscles get stronger, you need to add more weight—or other resistance—so you can still do only eight to 12 repetitions.”
3. With the right exercise you can get rid of trouble spots
The third of these exercise myths is a little spotty. Some people believe that if they exercise one area, it will cause fat to be removed from that area,” says Rosemary Lindle, a University of Maryland exercise physiologist.
“In our gym the men, who tend to store their fat in their abdomens, are on the ab machines, and the women are on the total hip machines for hours,” she notes. “But spot-reducing is a myth.”
Abdominal and hip exercises can strengthen and tone the muscles. But those muscles are underneath the “subcutaneous” layer of fat that gives the lovely appearance of flab. Only losing weight can get rid of excess fat, and where you lose the weight depends on your genes. Losing weight around the waist is easier than losing it at the hips.
4. Exercise burns lots of calories
“People have the mistaken idea that exercise is a fabulous way to lose weight,” says William Evans of the University of Arkansas for Medical Sciences. “But exercising doesn’t burn a lot of calories.”
Walking or running a mile burns about 100 calories. But sitting still for the same time burns about 50 or 60 calories. “So the extra you expend isn’t huge and people get discouraged at their slow rate of weight loss.”
Another misconception: You keep burning considerably more calories for a long time after you stop exercising. “Calorie expenditure is elevated for the first minute or two, but by five or six minutes the extra expenditure is pretty small, and by 40 minutes post-exercise, it’s back to where you started,” says Evans.
That doesn’t mean dieters should give up on exercise. The more you exercise, the more fit you’ll get. That means you’ll burn more calories because you can walk briskly or run for five miles instead of one. So instead of burning 100 calories, you burn 500 (that’s 250 more than if you had stayed on the couch).
5. If you don’t lose weight there’s no point in exercising
The fifth of the exercise myths is more than just a loser. What gets most people off the couch and into their walking shoes? It’s that unwanted flab that motivates most of us. It shouldn’t.
“Many people don’t see immediate weight loss and say it’s all for naught and stop,” says exercise expert William Haskell of Stanford University Medical School.
In fact, exercise has a laundry list of benefits beyond any impact on your next shopping trip. Among them: “It improves the ability of insulin to enter cells so it lowers the risk of diabetes,” says Haskell. “It also lowers the risk of heart disease by improving blood clotting mechanisms, lowering triglycerides, and raising HDL [‘good’] cholesterol.”
Exercise alters not only your risk of disease, but your quality of life, he adds. “In our studies, exercise improved sleep in people with modest sleep dysfunction,” that is, people who take a long time to fall sleep or who wake up frequently at night.
“The psychological benefits of exercise are frequently overlooked,” says Haskell. “Exercise isn’t a panacea, but it has consistently been shown to relieve both depression and anxiety.”
6. Weight gain is inevitable as you age
Most Americans get fatter as they get older…but they don’t have to. “It’s a matter of reduced physical activity levels and lower metabolic rate caused by a loss of lean body mass [muscle],” says JoAnn Manson of Harvard Medical School.
“The lifelong loss of lean body mass reduces our basal metabolic rate as we age,” says Arkansas’s William Evans. “It’s a very subtle change that begins between ages 20 and 30. The percentage of body fat gradually increases, and it produces an ever-decreasing calorie requirement.”
That’s because fat cells burn fewer calories than muscle cells. And a lower metabolic rate means that unless you eat less, you’ll gain weight over the decades.
But exercise can mount a two-pronged attack on middle-age spread and muscle loss. Any activity makes you burn more calories (so you’re less likely to wind up with an excess). And strength-training can offset the loss of muscle mass.
7. You can’t be fit and fat
The seventh of the exercise myths includes “the notion that all fat people are sedentary and unfit and at high risk of disease.” It is not true, says Steven Blair of the Cooper Clinic in Dallas, Texas. “Overweight and obese individuals who are fit do not have elevated mortality rates. We need to get off those people’s backs.”
8. No pain no gain
“Many people still believe that you have to work at a very high intensity in order to get a benefit,” says the Cooper Clinic’s Steven Blair.
In fact, moderate-intensity exercise lowers the risk of dying just as much as high-intensity exercise. The trick is making sure that the exercise is at least moderate-intensity—that is, equivalent to walking at a pace of three to four miles an hour.
9. If you can’t exercise regularly why bother
It takes ten to 12 weeks of regular exercise to become “fit”—that is, to improve your performance on a treadmill (a measure of your oxygen capacity). But your health can improve after that first brisk walk or run.
“Take a 50-year-old man who is somewhat overweight and typically has moderately elevated blood sugar, triglycerides, or blood pressure,” says Stanford’s William Haskell. “A single bout of exercise of moderate intensity—like 30 to 40 minutes of brisk walking—will lower those numbers.”
10. If you didn’t exercise when you were younger it could be dangerous to start when you’re older
One of the big exercise myths is that “many people think they’re too old to start an exercise program,” says Tufts University’s Miriam Nelson. “They think it’s unsafe because they have heart disease or diabetes or because they’re too out of shape to start.”
You’re never too old to start, says Nelson. And she ought to know. In one Tufts study, the participants were frail nursing-home residents whose ages ranged from 72 to 98. After just ten weeks, strength-training improved their muscle strength, ability to climb stairs, and walking speed. “When they see what a difference it makes, they’re thrilled,” says Nelson.
As for the all-too-common “I don’t have time to exercise,” Nelson responds, “somehow, you’ve got to make the time, or you’re going to have medical problems like heart disease, diabetes, or osteoporosis. And it will take a lot more time to deal with them than it takes to exercise.”
Sources: J. Amer. Med. Assoc. 272: 1909, 1994. J. Appl. Physiol. 86: 195, 1999. N. Eng. J. Med 330: 1769, 1994. J. Amer. Med. Assoc. 282: 1731, 1999.