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 
