ANAHEIM, Calif. - Women who run 40 miles a week get far greater health benefits than
those who run less than 10 miles, researchers found in one of the first studies of
strenuous exercise in women.
The finding challenges the idea that modest exercise provides almost the same benefits
as vigorous exercise, said the study's author, Paul Williams, an epidemiologist at the
University of California's Lawrence Berkeley National Laboratory.
"The question we were asking was: Does exercise have the same benefits in women
and men?'' The study showed that the benefits were "virtually identical,'' Williams
said.
Last year, Williams reported that the more men exercise, the more benefits they get,
even up to as much as 100 miles of running per week.
He described the research Wednesday at the annual meeting of the American Heart
Association.
In a related study presented at the meeting, researchers found that being overweight
seems to block many of the otherwise beneficial effects of exercise in older men. In other
words, mall walkers and other older men who exercise modestly might be getting little
benefit if they don't also lose weight.
And in a third study, scientists found evidence to support a bit of runners' folklore:
Coffee helps to boost performance.
Williams said he conducted his study partly in response to the recent recommendations
of the Centers for Disease Control and Prevention, which say American adults should do 30
minutes or more of moderate intensity exercise on "most days of the week.''
That may be good advice for women who get no exercise whatsoever, but it doesn't make
clear that more vigorous exercise can provide even greater benefits, Williams said.
"Women should attempt to exercise as much as is comfortable for them,'' Williams
said. "If they want a lot of benefit, they need a lot of exercise.''
The principal benefit that Williams found was a rise in HDL, or good cholesterol, which
protects against heart attacks. Women who ran 40 miles a week had an HDL of 69, 10 points
higher than the women who ran less than 10 miles a week.
That increase is associated with about a 29% lower risk of heart disease and a 45%
reduction in heart disease deaths, he said.
"Women are only about 25-30% of the running population,'' Williams said.
"That may be because they are less aware of the benefits.''
The study was conducted on 1,833 women selected from the subscription list of Runners'
World magazine and from women who returned questionnaires handed out at races across
the country.
The study of older overweight exercisers also found that a lot of exercise produced
extra benefits, because that meant patients were more likely to lose weight.
"The study shows that if you're obese, even if you train vigorously three times a
week or 45 minutes, there is no benefit in HDL cholesterol,'' said Dr. Leslie Katzel a
gerontologist at the University of Maryland School of Medicine.
To maximize the benefits of exercise, older men should be less than 20% above their
ideal weight, Katzel said.
The study of caffeine, by Bruce Hardy and colleagues at the Oregon Health Sciences
University in Portland, found in six young men that a dose of caffeine lowered blood
pressure and increased the heart's output.
That suggests that caffeine enhances the relaxation of the blood vessels caused by
exercise, the researchers said.
