The American Heart Association has classified physical inactivity as a major risk factor for heart disease.
Yesterday was the first time the association declared that a sedentary lifestyle is every bit as bad for your heart as smoking, high cholesterol or high blood pressure.
Previously, the association had recognized that lack of exercise played some role in the development of coronary artery disease, but that was not given the same weight as the other three factors.
Activity is so crucial to good health that doctors should assess their patients' exercise habits with the same concern that they take their blood pressure and cholesterol levels, a panel of heart experts said in a policy paper yesterday.
It also recommended that people do some kind of exercise, even as mild as walking, for 30 to 60 minutes, three to four times a week, to protect against cardiovascular disease.
"We're not telling people 'Hey, you have to enroll in a gym . . . or show up and do these power workouts,'" said Ileana Pina, a cardiologist at Temple University Hospital in Philadelphia, who was part of the Heart Association panel that drafted the guidelines. "We're saying 'Hey, just get off your duff and do something.'"
Heart attack is the leading cause of death in the United States, killing about 500,000 people a year. But the latest statistics from a federal survey of health habits found that only one-third of American adults exercise or play sports regularly.
Even among teen-agers, only 37 percent do some sort of sustained and vigorous physical activity three times a week, a 1990 survey by the federal Centers for Disease Control found.
Steven Blair, director of epidemiology at the Institute for Aerobics Research in Dallas, said in an interview that 20 to 30 percent of Americans do so little physical activity that they are at especially high risk for developing the clogged arteries that lead to heart attacks. He said calculations by CDC scientists show that about 250,000 deaths a year in the United States are due to such languor.
In its policy statement, the Heart Association said vigorous activities such as running, hiking, stair-climbing, bicycling, tennis, touch football and soccer were especially beneficial, but even less strenuous activities -- yard work, dancing, croquet and ping-pong -- were good for the heart.