Start of an era
The Cooper study, and others that followed, profoundly changed the thinking of many researchers. Many sports scientists came to believe that moderately intense physical activities such as walking, gardening, or cleaning house -- dubbed "exercise lite" -- could provide most of the health benefits of more conventional exercise. To lead author Steven Blair, PhD, and his colleagues, this meant that instead of exhorting people to strive for levels of exercise that most of them would never achieve, health professionals could urge their patients to engage in the kinds of exercise they might actually get out and do.
Even the U.S. surgeon general joined the ranks, issuing guidelines that encourage Americans to engage in "a minimum of 30 minutes of physical activity of moderate intensity (e.g., brisk walking) on most, if not all, days of the week." The era of "exercise lite" had begun.
Walking shoes became the rage. A magazine called Walking was born. And hoofing it through the neighborhood became the exercise of choice for many active Americans.
Not just a walk in the park
But a decade after the famous study's release, some researchers argue that we've been sold a bill of goods. "Exercise lite is to exercise what lite beer is to beer. It's pretty bland stuff," says Paul Williams, PhD, an exercise scientist at the Life Sciences Division of the Lawrence Berkeley Laboratory in California. "Exercise lite has given many Americans a false sense that a stroll through the neighborhood is all you need to stay healthy. Instead of pushing people to be more active, it's given them an excuse to do as little as possible."
One recent study, appearing in the June 30 Mortality and Morbidity Weekly Review, offers some support for Williams' contention. The researchers surveyed people who walk for exercise and found that only 26% walked briskly enough to achieve the "moderate intensity level" recommended by the U.S. surgeon general. In addition, a mere 34% walked the recommended four times or more a week.
Williams' studies at Lawrence Berkeley Laboratory suggest that the real health payoff comes to exercisers who crank up both the intensity and duration of a workout. In ongoing research with 55,000 runners from around the country, Williams has found that the more miles runners cover -- up to a very rigorous 40 miles a week -- the lower their risk of heart disease.
"The more exercise you do, and the more vigorous it is, the more you benefit," says Williams, whose findings were published in the January 1997 issue of Archives of Internal Medicine.