Does Exercise Really Make You Healthier?

Does Exercise Really Make You Healthier?
We examine five claims about the benefits of weightlifting and aerobics to see which carry the most . . . weight
By Coco Ballantyne January 2, 2009
The Department of Health and Human Services (HHS) late this year released its new Physical Activity Guidelines for Americans, calling for adults between the ages of 18 and 64 to exercise moderately (such as brisk walking or water aerobics) for at least two hours and 30 minutes or vigorously (running, swimming, or cycling 10 mph or faster) for at least an hour and 15 minutes weekly. The longer, harder and more often you exercise, the greater the health benefits, including reducing the risk of diseases such as cancer and diabetes, according to the recommendations, which were based on a decade of scientific research. Studies have shown that people who engage in the amount of exercise recommended by the feds live an average of three to seven years longer than couch potatoes, according to William Haskell, a medical professor at Stanford University who chaired the HHS advisory committee. But how exactly does exercise accomplish this? And what about claims by naysayers that exercise not only isn't healthy but may actually be bad for you? Is there any truth to them? In the past decade or so, various studies involving thousands of participants have shown that workouts lower the risk of heart disease. "Exercise has a favorable effect on virtually all risk factors of cardiovascular disease," says Jonathan Meyers, a health research scientist at the Palo Alto Veterans Affairs Health System in California. The reason, he says: when a person exercises, the heart muscle contracts forcefully and frequently, increasing blood flow through the arteries. This leads to subtle changes in the autonomic nervous system, which controls the contraction and relaxation of these vessels. This fine-tuning leads to a lower resting heart rate (fewer beats to pump blood through the body), lower blood pressure and a more variable heart rate, all factors that lower the risk of developing cardiovascular disease, he says.