|  How
Much Exercise Is Enough?
Your level of physical activity should depend
on your goals
The Institute of Medicine's new stand on physical
activity succeeded in one sense -- it sure raised
a few heart rates.
The private advisory group's call for 60 minutes
of physical activity each day seemed to double
the Surgeon General's guideline of 30 minutes
of exercise most days. The new advice was meant
to get people moving, but some experts were
moved to gripe.
"The concern is that individuals will
see this call for 60 minutes and think, 'My
gosh, now it's 60 and I can't even do 30,'"
says Edward T. Howley, Ph.D., with the American
College of Sports Medicine. "Sedentary
individuals might be dissuaded from physical
activity altogether."
But scientists who came up with the advice
say the dispute is an exercise in confusion.
The Institute of Medicine (IOM) is part of
the National Academy of Sciences, created by
the federal government to act as an independent
adviser on scientific matters. In a study on
diet, an IOM panel looked at the number of calories
thousands of people burn each day. It found
that folks with a healthy body weight take part
in about an hour of activity a day while sticking
to a sensible diet.
The panel measured all calories burned -- everything
from low-intensity movement such as climbing
stairs to high-intensity exercise such as tennis.
So the recommendation isn't based on a solid
hour of exercise. You can count short sessions
through the day with varied intensity levels.
The standard, though, is 60 minutes total of
moderately intense activity, such as walking
3 to 4 miles per hour.
"People are confusing physical activity
with exercise," says IOM panel member George
Brooks, Ph.D., a professor of integrative biology
at the University of California at Berkeley.
"If you walk to work, if you use the stairs,
that is physical activity. If you go for a half-hour
run, that's vigorous exercise, and it will be
about the energy equivalent of walking briskly
for an hour. So it's really a refinement of
the Surgeon General's report."
The 60-minute advice is aimed at weight control.
It does not rule out health benefits from lesser
levels of activity. Studies show that 30 minutes
of moderate activity a day lowers your risk
for heart disease and diabetes.
If you're sedentary, 30 minutes of moderate
activity is a good goal, says I-Min Lee, Sc.D.,
associate professor of medicine at Harvard Medical
School. She found in one study that as little
as an hour of walking a week halved the heart
disease risk in a group of sedentary, middle-aged
women. Still, she recommends more than that.
"Thirty minutes of moderate activity per
day still represents the low end of the scale,
which should be the goal if you are sedentary."
So your needs depend on your goals:
| • |
If you
want to keep your heart healthy and help
fend off diabetes, 30 minutes of moderate
activity most days of the week should
do. |
| • |
If you want to reap
those benefits and watch your weight,
follow the 60-minute advice. |
| • |
If you want to lose
weight, you must exceed the 60-minute
level, or keep up that activity level
while taking in fewer calories. |
Any movement that raises your heart rate counts.
To burn more calories, try higher-intensity
activities like jogging or swimming.
Don't let confusion keep you on the couch.
"Some people might say, 'I'm not going
to exercise until [the scientists] get it right,'
and that's not what we want," Dr. Lee says.
Get the lead out
You can build physical activity into sedentary
situations.
Desk jobs: Take the stairs, not the
elevator. Walk to a co-worker's office rather
than phoning. Take a walk (10 to 30 minutes)
during your lunch hour. Get up, stretch and
move at least once an hour.
Autos: Walk instead of driving for
short trips. Wash the car yourself rather
than using an automatic car wash. Park at
the edge of the lot.
TV: Work out on a stationary bike
or treadmill while you watch. Get rid of the
remote control. Replace a half-hour of viewing
each day with exercise.
Burning calories
Calories burned in half an hour by a 150-pound
adult:
Basketball 288
Gardening 162
Golf (no cart) 198
Raking lawn 162
Running (11.5 min/mile) 324
Step aerobics 252
Swimming 216
Tennis 252
Walking (3.5 mph) 144
Washing car 162
Copyright 2003 Health
Ink and Vitality Communications, 780 Township
Line Road, Yardley, PA 19067, 1-800-524-1176
Publication: Health & You
Publication Date: Summer 2003
Author: Steve Cline
Source: Institute of Medicine
Online Editor: Dianna Sinovic
Online Medical Reviewer: Cynthia Godsey, M.S.N.,
F.N.P./C., Gordon Lambert, M.D.
Date Last Modified: 7/15/03
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