Karen
Mayes, 45, is no marathoner, but she’s in
excellent shape. Almost every day for the last 10
years, Mayes has walked up and down the hills in
her tree-lined neighborhood in Cleveland Heights,
Ohio. A few years ago she added a Pilates class
to tone her muscles.
“My goal is to still be able to do things
when I’m 80,” she says. Even over the
holidays, Mayes trooped through snow and ice for
a payoff she knew she could count on. “I feel
better, sleep better, eat better and look better,”
she says. “Exercise is a great thing.”
If only the rest of America felt the same way. Unfortunately,
too many of us sit for hours at desk jobs, relying
on e-mail, cell phones and, when we finally get
home, the TV remote. Technology has fast-forwarded
our minds, but slowed our bodies — and dangerously
so. One in four adults in this country leads a completely
sedentary lifestyle and more than 60 percent of
the population doesn’t do enough physical
activity to gain vast health benefits, chief among
them a dramatic drop in the risk of dying prematurely.
We all know we should exercise. But we’re
too busy and too tired. And we’re also increasingly
confused: How much is necessary? Is it 60 minutes
(gasp!) most days of the week, as the Institute
of Medicine suggested last fall? Or 30 minutes?
Three days a week or five? Running or mall walking?
Researchers are attacking those questions and they’re
delving even further into how physical activity
affects our bodies at the molecular level. No matter
how far the science goes, though, there’s
one finding that will remain indisputable: any amount
of exercise is better than none. “Being active
and fit is good for you whether you’re young
or old, man or woman, tall or short, skinny or fat,”
says Steven Blair, president of the Cooper Institute
in Dallas, a health-research group.
A PUBLIC-HEALTH CHALLENGE
That’s
not a revelation. Scientists dating back to Hippocrates
have known that exercise bolsters health. But it
wasn’t until the mid-20th century that data
about the specific benefits of physical activity
began building to what is now a breathtaking list:
lower cholesterol and blood pressure; a reduced
risk of heart disease, stroke, osteoporosis, diabetes
and colon cancer; strengthening of bones, joints
and muscle, and an improvement in anxiety and depression.
No pill will ever come close to being such an elixir.
Or such a cost-saver: the Centers for Disease Control
and Prevention estimates that getting inactive Americans
exercising could save this country $76.6 billion
a year in dollars otherwise spent on treating chronic
disease. “Inactivity,” says Russell
Pate of the University of South Carolina’s
school of public health, “is one of the great
public-health challenges of this century.”
Our sedentary habits led public-health officials
to pursue a dramatic shift in exercise recommendations
in the mid-1990s. For years, the emphasis had been
on getting the heart revved at least three times
a week through vigorous aerobic activity like running,
as recommended by the American College of Sports
Medicine in 1978. But as it became increasingly
clear that only a sliver of the population was actually
going to leap up and start sprinting, researchers
realized there was an urgent need to scale back
expectations. In 1996, the surgeon general issued
a landmark report on physical activity and a bold
new directive: at least 30 minutes of moderate-intensity
exercise — the kind you can fit into your
daily routine, like brisk walking, bicycling and
gardening — on all or most days of the week.
Rather than get a handful of people superfit, officials
theorized, let’s get the masses up and moving.
Still, vigorous exercise may offer even
greater benefits than moderate-intensity activity.
In a study published in The Journal of the American
Medical Association in October, Harvard researchers
found that men who ran for an hour or more each
week reduced their risk of heart disease by 42 percent
compared with nonrunners. Men who walked briskly
for more than half an hour per day had an 18 percent
reduction, and the faster their pace, the greater
the drop in risk. “The more you do, the less
heart disease you’re going to have,”
says study coauthor Dr. Mihaela Tanasescu. There
was more good news for runners in a study published
in November. Members of a California runners club
over the age of 50 who ran for about four hours
a week dramatically reduced their likelihood of
disability later in life compared with a control
group who ran an average of 20 minutes per week.
And the controls had a death rate three times higher
than the runners during the study’s 13-year
follow-up.
PICKING UP THE PACE
For
those who are already active, picking up the pace
is a worthy goal. But right now, experts are focused
on the positive and growing links between exercising
more often at a moderate pace and good health. In
a study of 73,743 postmenopausal women published
in September, researchers led by Dr. JoAnn Manson,
chief of preventative medicine at Harvard’s
Brigham and Women’s Hospital, found that women
cut their risk of heart disease by 30 to 40 percent
whether they exercised vigorously in sports like
jogging, swimming and aerobics or walked briskly
for 30 minutes a day. “The important question
is, does moderate-intensity exercise provide benefit?
And the answer to that is an unqualified yes,”
says Blair. If every American walked briskly for
30 minutes a day, he says, “the public-health
battle would be won.”
So where does the 60-minute recommendation fit in?
When it was issued in September, the Institute of
Medicine report seemed to fly in the face of the
surgeon general’s guidelines, but the two
may not be quite as incompatible as they seem. The
30 minutes is aimed at reducing the risk of chronic
disease in the future. The 60 minutes, on the other
hand, is paired with dietary recommendations and
focuses on weight control in the present. Researchers
found that among healthy people with a body mass
index (a ratio of weight to height) of less than
25 (with 18.5 to 25 being desirable), 60 minutes
of physical activity was necessary to maintain body
weight and avoid excess gain. But the finding should
not negate what the CDC recommends, says Dr. Ben
Caballero, who was a member of the Institute of
Medicine panel and is director of the Center for
Human Nutrition at Johns Hopkins school of public
health. The two guidelines, he says, “are
complementary.”
If you’ve made it to even half an hour a day,
congratulations. You’re near the top of a
very small heap. You deserve a big glass of water.
The rest of us, however, need a kick. Start by setting
goals and “make sure those goals are realistic,”
says Bess Marcus, director of physical-activity
research at Brown University’s Centers for
Behavioral and Preventative Medicine. Don’t
focus on weight loss; reducing your dietary intake
will help a lot more in that department. Think instead
about your health, which will improve no matter
how much you weigh and whether or not you lose any
pounds. If you’re investing in your first
pair of athletic shoes, walk for a few minutes a
day until you work up to 30 or more. A brisk pace
is critical: to get the full health benefits, you
must complete a mile in 15 to 20 minutes max. You
should feel your heart beat faster, your breath
quicken, your sweat drip. “We want to avoid
the Sunday stroll,” says Marcus. Consider
using a pedometer, which tracks the number of steps
you take per day, and aim for 10,000. Make physical
activity part of your regular daily routine (no,
you don’t have to go to a gym), and make it
a priority. And yes, you can accumulate that half
hour throughout the day. Studies have shown that
exercising in three 10-minute sessions is comparable
to a workout in 30 minutes all at once. “Whether
it’s walking to work, walking a little extra
after you park the car or doing planned exercise,
everything counts,” says the CDC’s Dr.
Michael Pratt.
GREATER STRENGTH
Any exercise program should also include resistance
training for 20 minutes three times a week, using
weights or exercise bands, or doing push-ups or
squats. Weight training increases muscles and improves
bone density — critical for baby boomers who’d
rather bungee-jump than use a walker. “There’s
no other way you retain muscle mass and strength,”
says William Haskell, an exercise specialist at
the Stanford School of Medicine. Better strength
also means fewer falls, which are the leading cause
of death from injury in people older than 65. And
new research suggests resistance training can even
be good for the ticker, too: the Harvard runners
study found that men who trained with weights for
30 minutes or more per week cut their risk of heart
disease by 23 percent.
Physical activity is as imperative for kids as it
is for adults. Nearly half of all teens and young
adults between the ages of 12 and 21 are not vigorously
active on a regular basis. That’s not surprising:
the vast majority of kids travel to school by car
or bus and watch more than three hours of television
a day. The University of South Carolina’s
Pate says kids’ exercise patterns are heavily
influenced by the environments in which they spend
large chunks of time. “A kid who goes home
and puts a video in the VCR is going to be a lot
less active than a kid who spends time at the Boys
& Girls Club,” he says. Parents can make
a positive impact by supporting their children’s
involvement in sports, driving them to games or
clubs and playing with them in the park.
Even with all the evidence that has accumulated,
researchers are continuing to dig deeper into the
connection between exercise and the body, and at
an even more microscopic level. A study led by Duke
University researchers published in November zeroed
in on the precise changes in cholesterol after exercise.
Researchers found that overweight, sedentary people
who were assigned weekly exercise programs produced
more and larger HDL particles (the good kind of
cholesterol) and fewer LDL particles (the bad) than
those who did no exercise. Other researchers are
looking at how cells activated during exercise regulate
glucose, a critical link in the onset of diabetes.
And scientists like Frank Booth, of the University
of Missouri-Columbia, are examining the genetic
underpinnings. Booth believes humans were programmed
to be physically active: our genes, in other words,
expect us to be moving. By becoming sedentary, he
says, we’ve messed with the blueprint and
are now suffering the consequences of disease. Rather
than study the benefits of doing some exercise,
Booth is waging war against the detrimental effects
of doing none.
As the science gets more finely tuned, doctors may
one day be able to prescribe a specific dose of
exercise at a specific intensity for a specific
condition, says Duke’s Dr. Bill Kraus: a 25-year-old
who wants to get fit, for example, versus a 55-year-old
with high cholesterol or a 70-year-old diabetic.
Behavioral researchers are also looking hard at
how to get people better motivated, one of the greatest
challenges in the field. And others are studying
the design of our suburbs, cities and schools (are
there sidewalks or bike paths?), figuring out how
to fit exercise more naturally into our daily lives.
In the meantime, it’s up to you. If you’re
not bounding off the couch by now, consider two
more pieces of data: a recent Stanford study of
more than 6,000 men found that tolerance for exercise
(tested on a treadmill) was a stronger predictor
of risk of death than high blood pressure, smoking,
diabetes, high cholesterol and heart disease. And,
finally, in the study of 73,743 women, just sitting
for longer periods of time predicted an increased
risk of cardiovascular disease. Heart disease, by
the way, is the nation’s No. 1 killer. So,
stand up. And get moving.
With
Joan Raymond
© 2003 Newsweek, Inc., Jan.
20, 2003
