A Little Exercise Is Better Than None
Burning as few as 150 calories a day by walking the dog, washing the car, puttering in the garden and climbing the stairs can reduce the risk of heart disease, high blood pressure, cancer and diabetes, according to the first surgeon general’s report on physical activity, issued Thursday.
In place of trips to the gym or the jogging track, the report says, a moderate level of exercise can be achieved by doing any of a number of ordinary chores at a brisk pace. But, it says, the majority of Americans simply do not perform them.
After 30 years of trying to convince Americans that exercising is good for them, the government has little to show for it. According to the report, 60 percent of Americans do not exercise regularly, including 25 percent who do not exercise at all.
The lack of activity contributes to a number of diseases and to obesity. Various surveys have found that a third of Americans are now obese, up from fewer than 25 percent in the early 1960s.
The report is an effort to clear up confusion among the public about how much exercise is needed to be effective.
In the 1970s, people were told that high-intensity aerobic exercise was necessary. In the 1990s, studies have shown that moderate exercise is also beneficial.
The issue was somewhat clouded last year, however, by a Harvard study that seemed to indicate that living longer required hard exercise.
An editor of the surgeon general’s report, Dr. Steven Blair, director of epidemiology at the Cooper Institute for Aerobics Research in Dallas, said the Harvard finding was “an anomaly” because the study had compared only two categories of physical activity: vigorous, in one category, and everything else, ranging from light to moderate, in the other. It did not, he pointed out, compare vigorous exercise with moderate exercise alone.
“None of us has ever felt that there is any evidence that light activity provides any benefit at all,” Blair said.
On the other hand, “people who go from a sedentary life style to moderate activity cut their heart disease mortality rate in half,” he said.
Still, while promoting the benefits that can be achieved by exercise that is only moderate, the report acknowledges that the more time devoted to an activity and the greater its intensity, the greater the benefits.