Gardening, walking and other mild exercise are better than nothing, as the President’s Council on Physical Fitness and Sports pointed out in issuing its current 30-minutes-a-day recommendation.
But when it comes to exercise, a new study of more than 8,000 runners advises, more is better still.
The runners study found that “substantial health benefits” come from exercise at levels above the recommended minimum, and these benefits steadily accrue in exercise of up to at least 50 miles a week.
The study included 8,283 male recreational runners, averaging 45 years old, who had no history of heart disease or cancer and were not taking medications that could alter their cholesterol level. The more miles they ran each week, the more favorable their coronary heart disease risk factors, such as blood pressure, body weight and levels of cholesterol and triglycerides (fatty acids) in the blood.
As a result, the overall coronary heart disease risk - or estimated chance of having a heart attack in the next 10 years - was 30 percent lower for those who ran 40 to 50 miles a week than for those who ran less than 10 miles a week. Age, level of education and consumption of fish and alcohol did not vary significantly among the groups.
Running more miles per week tended to raise the blood level of high-density lipoproteins (“good” cholesterol) and lower the level of low-density lipoproteins (“bad” cholesterol). A separate report found similar cholesterol changes in female runners.
The findings, based on data from the National Runners’ Health Study, appeared recently in the Archives of Internal Medicine. The data were analyzed by Paul T. Williams of the Lawrence Berkeley National Laboratory in Berkeley, Calif.
Williams cautioned that vigorous exercise can carry risks. Sedentary men, particularly those over 40, should not start a running program without a physical exam, he said.
In an accompanying editorial, Steven N. Blair of the Cooper Institute in Dallas noted that the federal fitness guidelines are aimed at sedentary Americans, while Williams’ study included only experienced runners. The biggest public health benefit, he said, would come from getting unfit people to exercise at least a little.
Both groups can agree, Blair said, “that some activity is better than none, and more is better than a little.”