No Time for Long Walks? Do Short Ones

It doesn’t take even as much as brisk walking to reduce the risk of heart disease --an hour’s amble will be enough, a study says.

Women who walked as little as one hour a week, even at a gentle pace, had about half the risk of coronary heart disease faced by women who got no physical activity, the study found.

The study indicates women can benefit even with less than 30 minutes of brisk walking on most days of the week, the level that current federal guidelines consider a minimum.

“It’s very encouraging. So long as you walk at least an hour a week, it doesn’t matter how fast or how slow you walk,” researcher I-Min Lee said. “Even doing a little bit can be helpful.”

One of Lee’s Harvard University colleagues warns, however, that the results reported in the Journal of the American Medical Assn. are not meant to encourage laziness. The report shows that even a little exercise is better than none, but more is better than a little, said Dr. JoAnn E. Manson. And the benefits in the new study might not be as great as the study makes them appear, she said.

The researchers looked at 39,372 health professionals, ages 45 and older, who kept track of their health status in a project called the Women’s Health Study. The scientists tracked the women for an average of five years and found 244 cases of coronary heart disease.

One focus of the study was walking because many women like to walk, Lee said.

The study found that women who did more vigorous exercise had a lower risk of heart disease. But among women who did not do vigorous exercise, those who at least walked an hour during the week had a lower risk than that faced by completely sedentary women.

Lee hopes this may encourage some activity by sedentary women who don’t want to do the total of about three hours a week that is recommended in the current guidelines. “If you give them an easier goal, they are more likely to try to reach that,” she said.

Their payoff would be a risk reduction equivalent to that of losing weight or giving up smoking, Lee said. For instance, smokers who walked at least an hour a week cut their heart disease risk to the levels faced by sedentary nonsmokers, she said.

Women who don’t think they can give up all their health-risk bad habits might at least modify one, Lee said.

Smokers, for instance. “I would not say ‘Give up trying,’ but if they are not able to kick the habit, I would say they do benefit themselves by being physically active,” Lee said.

As for the overweight, “It is extremely difficult for overweight people to lose weight. But if they cannot lose weight despite trying, I would say they should go and be physically active,” Lee said. “It is so good for them.”

However, because the findings are so new, Lee would rather see women stick with the current guidelines--a view echoed by Manson, who harbors some doubts about the study.

It doesn’t sound right that women can get this much benefit from activity that takes as little as 8 1/2 minutes a day, when research up to this point had indicated 30 minutes a day was the minimum, Manson said. “I think it’s way too little. I don’t want people to think it’s a quick fix,” she said.

It may be, for instance, that women who had reported once that they ambled may have gone on afterward to walk briskly, Manson said. The JAMA study’s snapshot of their activity habits would not have spotted that, but it might be a reason for the lower rate of heart disease, she said.

The study may be right in saying that some exercise is better than none, but 30 minutes of brisk activity is still likely to be better than 8 1/2 minutes of light activity, said Manson. The professor of medicine at Harvard Medical School and chief of preventive medicine at Brigham and Women’s Hospital is coauthor of a new book, “The 30-Minute Fitness Solution: A Four-Step Plan for Women of All Ages.”

The new study “confirms that doing something is better than doing nothing,” said researcher Steven N. Blair of the Cooper Institute for Aerobics Research, who was not involved in the study. He expected the new findings will be considered as experts review the current federal standards.

Being more active than the study found is better still, said Blair, who was instrumental in developing the current guidelines endorsed by the Centers for Disease Control and Prevention, the Office of the Surgeon General and the American College of Sports Medicine.

But Blair said the new findings would be considered as experts review the current federal standards.