EMBARGOED FOR RELEASE: 3 p.m. (CT) SUNDAY, JANUARY 26, 1997
Media Advisory: To contact Paul T. Williams, Ph.D.,
call Jeff Kahn at 510/486-4019.
To contact Steven N. Blair, P.E.D.,
call Leah Kay Gabriel at 214/239-7223.
MORE IS BETTER WHEN IT COMES TO EXERCISE Long-distance runners shown to have lower risk for coronary heart disease
Exercising beyond current minimum guidelines (30 minutes a day most days of the week) can provide substantial health benefits, according to an article in the January 27 issue of the AMA's Archives of Internal Medicine.
Paul T. Williams, Ph.D., from the Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, Calif., examined the dose-response relationship between coronary heart disease (CHD) risk factors and vigorous exercise above the recommended minimum levels. Williams compared physician-supplied medical data with reported distance run by 8,283 male recreational runners participating in the National Runners' Health Study.
The Centers for Disease Control and Prevention and the American College of Sports Medicine recommend that adults should accumulate 30 minutes or more of moderate intensity physical activity over the course of most, preferably all, days of the week.
Williams found that CHD risk decreased significantly with each 16-kilometer (km) (10 mile) increment in distance run each week, up to 64 - 79 km per week. Over a 10-year period, men who ran 64 km or more per week have a 30 percent lower risk of CHD than those who ran less than 16 km per week.
Williams found that when compared with runners who ran less than 16 km per week, long-distance runners of at least 80 km/week were 2.5 times more likely to have high levels of high-density lipoprotein cholesterol (the good cholesterol). Long-distance runners also had half the prevalence of hypertension, and a reduction of more than 50 percent in the use of medications to lower blood pressure and cholesterol levels. The data did not exhibit a point of diminishing return to the health benefits of running at any distance less than 80 km/week.
Williams concludes: "It is important to emphasize that there are some risks associated with vigorous exercise that may increase with intensity and duration. Men who intend to begin a running program should have a recent physical examination. Current guidelines recommend a symptom-limited, maximum exercise test for men who are 40 years of age or older, men with abnormal physical examinations, and men with two or more coronary risk factors."
Editorial: Lack of Physical Activity a Public Health Problem
In an accompanying editorial in this week's Archives of Internal Medicine, Steven N. Blair, P.E.D., from the Cooper Institute, Dallas, Texas, writes: "... We must carefully evaluate the benefit-risk ratio for various activity doses. Excessive mileage may increase the frequency and magnitude of musculoskeletal injuries, chronic fatigue, amenorrhea (absence of menstrual periods), depressed immune function, and other overuse problems or possibly even increase disease incidence. While we all continue this scientifically and intellectually challenging work, we can probably agree on the importance of physical inactivity as a public health problem in the U.S.
"We further agree that some activity is better than none and more is better than a little. There remains the major task of promoting physical activity and encouraging sedentary individuals to become more active to realize the many health benefits that come from such change in behavior. Primary care physicians can play an important role in this effort, and we hope [they] will take part by assessing [their] patients' activity patterns and encouraging the sedentary to become more active."
Editor's Note: The Williams study was supported in part by the National Heart, Lung and Blood Institute (NHLBI). The Blair editorial was supported in part by the National Institute on Aging and the NHLBI.
# For more information: contact the AMA's Jim Michalski at 312/464-5785. email: [email protected] AMA web site: http://www.ama-assn.org
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