You've Got to Step Up Your
Exercise Intensity and Time
By Nanci Hellmich -
to Stay Slim and Healthy
Americans need to get real when it comes to
controlling their weight - some people may need to do an hour or more of
physical activity a day, and intensity matters, obesity experts say.
The bar for exercise in the United States
was once high, but almost a decade ago a moderate-activity alternative was
offered that encouraged people to walk briskly or move more for a minimum of a
half-hour a day.
The goal was to get sedentary Americans to
do something, anything. But many people didn't realize that 30 minutes of
activity might not keep their waistlines under control. Now the pendulum is
A report last fall from the National Academy
of Sciences' Institute of Medicine called for 60 minutes or more a day of
activity to prevent weight gain and get additional health benefits. This advice
comes as more than 120 million people in the United States are overweight or
"People have got to stop kidding themselves
about what it takes to control weight," says George Blackburn, associate
director of the division of nutrition at Harvard Medical School. "They can't
take a little stroll and think they are doing themselves any good. You need the
intensity and you need the time, at least 60 minutes."
For about half of the time, you need to be
doing something that makes you break a sweat and breathe heavily, he says. The
rest can be 10-minute periods of more moderate activity.
James Hill, an obesity expert at the
University of Colorado Health Sciences Center in Denver, says: "If everybody
did 30 minutes of activity a day, it would be huge for public health. Would it
make everybody lean? I don't think so."
Exactly how much exercise you need depends
on genetics, muscle mass, your diet, how much you weigh, whether you've lost a
lot of weight and other factors, Hill says. Most people will have to figure out
for themselves exactly what it takes.
Still, only about a third of adults in the
United States do enough to meet the moderate-activity guideline.
Experts have long debated the best exercise
prescription. For years people were urged to get 20 to 60 minutes of continuous
moderate- to high-intensity aerobic activity three or more times a week and to
do weight training at least twice a week.
Then, in 1995, scientists said the research
showed that adults would get health benefits from accumulating 30 minutes or
more of moderate-intensity activity on most, preferably all, days of the week.
People could walk briskly, swim, golf, rake leaves, dance, vacuum. The activity
could be done in 10- and 15-minute segments, as long as it added up to 30
minutes or more. The bottom-line message: It's no sweat if you don't sweat.
Experts hoped this flexibility would appeal
to sedentary Americans who had been left in the dust by the fitness craze. It
was meant only to complement the earlier guidelines. People who wanted to work
out longer were encouraged to do so.
But somewhere along the way the
moderate-activity message got diluted.
"Some people have interpreted the guideline
as 'anything counts,' " says Russ Pate, a professor of exercise science at the
University of South Carolina. "That was not the intention and never was the
For instance, dusting the house or strolling
through the mall doesn't meet the standard. Intensity matters. The pace has to
be challenging enough that you can feel your heart beat more rapidly and your
If you are meeting the 30-minute guideline
and your weight is inching up, then you probably need to do more, Pate
Some people may have more success at weight
loss and avoid putting the pounds back on if they do 45 to 60 minutes a day of
moderate-intensity exercise, says JoAnn Manson, chief of preventive medicine at
Harvard's Brigham and Women's Hospital in Boston.
They can lose weight by doing 30 minutes a
day, but they may need to cut more calories, she says. Another option is to
work out harder. Manson also recommends strength training at least 20 minutes
two times a week to increase muscle, which burns more calories.
She has done several studies that show the
many health benefits of physical activity and is a strong supporter of trying
to do at least three hours of moderate exercise a week.
To do that, Manson advises wearing a
pedometer and aiming for walking 10,000 steps, or about 4 or 5 miles a day.
About half of those steps can be done through a structured activity like taking
a brisk walk a couple of times a day, and the others can come from climbing
stairs or walking across the mall.
"Despite all the technological advances in
modern medicine, regular physical activity is as close as we've come to a magic
bullet for good health," Manson says. "So, find activities you enjoy and do