Even the act of standing up will help lower the risk of heart disease, and taking a brisk walk will do even more.
That's the message of a five-year study of almost 74,000 post-menopausal women between the ages of 50 and 79 who are participating in the Women's Health Initiative.
One expected finding, says a report in tomorrow's New England Journal of Medicine, is that women who walk or exercise vigorously for 30 minutes a day, five days a week, reduce their risk of heart attack and stroke by at least 30 percent. But the study also found that just standing up reduces cardiovascular risk as well.
"We looked at what the risk is of being totally sedentary," says Dr. JoAnn E. Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital and lead author of the report. "Women who spent fewer than four hours a day sitting had a lower risk than those with more prolonged sitting."
The basic message of the study, that exercise is good for the arteries, is not new, Manson acknowledges; that has been shown for both men and women. What this report adds, she says, is proof that the benefit applies to all ethnic groups.
"Most previous studies were done in white populations," she says. "We extend the findings to an ethnically diverse population."
To be precise, African Americans (5,661 women), Hispanics (2,880), Asian/Pacific Islanders (2,288) and American Indian or others (1,340). The results were consistent.
"Walking and vigorous exercise were associated with similar risk reductions, and the results did not vary substantially according to race, age or body-mass index," says the journal report. "A brisker walking pace and fewer hours spent sitting also predicted lower risk."
But that last sentence shouldn't deter a woman from doing something physical, Manson says. The report should help kill a long-standing belief by some experts that only vigorous physical exercise is good you, she says. "It's the 'no pain, no gain' dogma," Manson says. "This study suggests it is an outdated notion."
Encouraging women -- and men -- to do something physical is an urgent need, she says, because we are in "a public health crisis," with 75 percent of Americans getting less than the 30 minutes of exercise five days a week recommended by the American Heart Association and the American College of Cardiology.
There actually is a good case for upping that quota, says Dr. Paul D. Thompson, chief of preventive cardiology at Hartford Hospital in Connecticut, who wrote an accompanying editorial. "The present recommendations are good, but they were never intended to be the ideal amount or maximum amount, just something you could achieve easily," he says.
For optimum health, Thompson says, "You're better off doing an hour a day." Indeed, he says, "If you look at the bulk of information on exercise, more is always better. I don't think we have reached a point where we can say that someone can do too much exercise."
But this is a world of television viewers and couch potatoes, Thompson quickly acknowledges, and "the real question is how we get more people to do more exercise."
One thing that could help is knowledge of the mechanism by which exercise helps the arteries, which we don't have now, he says. "We'll have a better handle on how much exercise is best when we have a better understanding of what the mechanisms are," Thompson says.
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