Exercise rights--and wrongs
An hour workout or 30 minutes? Walk or run? Does gardening count?
The day after Thanksgiving in 1967, Ralph Paffenbarger laced up his Army boots and went for a jog. The physician barely made it to the end of the block. He was out of shape, and the boots didn't help. So what made Paffenbarger run? His research into heart disease: He was among the first to show that regular and vigorous exercise dramatically cut the danger. "I decided exercise was something I should be doing," says Paffenbarger, now 80 and a professor emeritus at Stanford. His endurance improved, as did his footwear, and he went on to race in 151 marathons. His research became the basis for fitness recommendations from the American College of Sports Medicine.
Paffenbarger took his own advice and ran with it. But confusion has kept many others from doing the same. Though fitness has proved to be a hedge against obesity, heart disease, high blood pressure, stroke, diabetes, cancer, and osteoporosis, people are terribly mixed up about the right kind of exercise to do to get these benefits.
Do we need long workouts to combat heart disease, or will short, intense ones do the trick? For cardiovascular fitness and other health benefits, the surgeon general advises 30 minutes of moderate exercise most days of the week. But not long ago, the recommendation was for 20 minutes of more vigorous exercise, three times a week. A full hour of moderate exercise every day is the prescription from the Institute of Medicine. Then there are notions about puttering in the garden, ballroom dancing, or vacuuming as a replacement for hitting the gym.
"Most consumers are scratching their heads and saying `What should I do?' " says James Rippe, a cardiologist at Tufts University. Their befuddlement could be why, despite all the pleading from doctors, only about 25 percent of Americans get enough exercise, according to the Centers for Disease Control and Prevention.
Avoiding illness. What you should do depends on your health history, your weight, and your goals. Cholesterol skyrocketing? Jog several miles each week and hit the rowing machine. Have more than a few pounds to lose? You may need to put in an hour or more a day. Concerned about bone loss? Pick up those weights.
For the fortunate folks who are at a normal weight, who are in good health and want to maintain it, 30 minutes of moderate activity, five to seven days a week, is enough. Do this and your risk of disease declines, no matter your age, sex, or race. "You'll get substantial benefits, including a 50 percent reduction in heart attack, a lower risk of colon cancer, and probably a lower risk of breast cancer and Type II diabetes," says Steven Blair, research director at Dallas-based Cooper Institute, which studies exercise and health.
The claim is backed up by years of studies showing that people with moderate exercise patterns have lower disease risks. Why? Exercise gets things moving in the body. Better blood flow to the muscles helps move sugar from blood to muscle cells and so lowers diabetes risk by keeping blood sugar levels under control. In the case of cancer, the mechanisms are less clear. Because exercise keeps your digestive system moving, it may reduce the time colon tissue is exposed to carcinogens. That could cut the risk of colorectal cancer, says Lisa Callahan, medical director of the Women's Sports Medicine Center at the Hospital for Special Surgery in New York.