Stepping Up Activity Boosts Value of Exercise, Study Finds

In the first study of the heart disease risks of a large group of serious runners, researchers found that although moderate exercise is good, the benefits continue to climb even at the most intense levels of activity.

Runners who logged 40 miles a week, for example, had a lower risk of heart disease than runners who covered 30 miles a week.

Current U.S. government guidelines emphasize moderate exercise for sedentary people but do not emphasize the continued benefits for more serious exercise enthusiasts.

As a result, some serious exercisers may be discouraged from continuing, believing that they are not getting any additional benefits, said the study’s author, Paul Williams, a researcher at the Lawrence Berkeley Laboratory in Berkeley.

He discussed the findings Wednesday at the annual meeting of the American Heart Assn.

Last year, the federal Centers for Disease Control and Prevention and sports-medicine specialists recommended that every American get 30 minutes of moderate exercise most days of the week.

Williams said that’s an excellent suggestion for the 78% of Americans who engage in little or no physical activity. But the statement seemed to suggest that more intense exercise had little benefit.

Peter Wood of Stanford University, another authority on exercise and heart disease, agreed with Williams that that is not true.

Many of the risk factors for heart disease--including body fat, cholesterol, blood pressure and triglycerides--continue to improve with more intense exercise, Wood said.

In a study of nearly 7,000 male runners recruited from the readers of Runner’s World magazine, Williams found, for example, that 12% of runners who covered less than 10 miles per week had dangerously low levels of good cholesterol. But that was true of only 2% of runners who ran 40 to 49 miles per week.

Levels of good cholesterol climbed in a direct relationship with the number of miles that runners covered each week, he found. Total cholesterol also dropped with increasing mileage. And an indicator of body weight likewise declined.

“People ask how much is enough,” Wood said. “I always say it’s like money: The more, the better.”