By Suz Redfearn
Special to The Washington Post
Tuesday, October 1, 2002; Page HE01
If a pill could significantly lower the risk of heart attack, diabetes,
stroke, osteoporosis and breast and colon cancer while reducing weight,
cholesterol levels, constipation, depression and impotence and also increase
muscle mass, flatten the belly and reshape the thighs even as
it reduced the risk of age-related dementia and made you better-looking
-- and had no negative side effects -- there would be panic in
the streets. The American economy would tip into chaos. The military would
have to be called in to secure supplies of the medication.
Luckily, there is no such pill.
But a large and growing body of credible research demonstrates that taking
a good walk most days of the week can deliver all of the
health benefits cited above and more (although we admit the "better-looking"
part is harder to prove).
Yes, walking. You know: one foot in front of the other, repeat, rinse,
repeat. A mode of exercise formerly considered the domain of the
elderly, the infirm and others incapable of or unwilling to do anything
more brow-dampening.
What's difficult to figure is why so many people -- including several of
the individuals who have labored to produce this special issue of the
Health section (!) -- do not bother to do it.
According to the Centers for Disease Control and Prevention (CDC), somewhere
near 75 percent of the U.S. population fails to get 30
minutes of daily exercise, whether that's walking or some more strenuous
form of sport or recreation. Approximately one-third live a
life offically defined as sedentary.
Worse is the recent news that 30 minutes a day may not be enough. Last
month, the National Academy of Sciences upped the ante, telling
Americans to aim for 60 minutes of moderately intense activity per day.
The CDC estimates that only 3 percent of Americans exercise 60
minutes a day.
Why we're not out there walking is a mystery. It is, after all, virtually
free, safe, pleasant, easy to do and hard to get wrong. It requires no
special equipment except (maybe) a pair of shoes. So why are we Americans
avoiding it (and other less popular forms of moderate
physical exercise) to the point that we're creating an epidemic of obesity
and scary upticks in the many diseases and conditions
associated with it?
Could it be that we've filled our lives so full of work and other obligations
that we have no energy left for the one thing most likely to keep
us strong and healthy for the daily battle?(Sure.) Can it be that our communities
and cities have been engineered in ways that
discourage or punish those who try to walk? (Yup, that too.) Can it be
that nobody's figured out how to make much money from other
people's walking habits, so there's no great commercial force urging us
to walk, nothing comparable to the marketing efforts trying to get us to
drink
sodas, order pizzas and buy new cars? (We think so.)
And can it be that some people just haven't had a recent reminder about
all the good things walking can
do, haven't heard some expert opinions on how to go about it and haven't
checked out all the resources
they can use to begin walking to improve their health? (We hope so, because
that's what we're
providing in the Health section this week.)
How Walking Works
Accepting that an activity as basic as walking can have powerful benefits
may require updating your
thinking about exercise.
"We used to think that exercise had to hurt, and you had to bleed and throw
up to accomplish
anything," said Susan Johnson, director of continuing education at the
Cooper Institute in Dallas, which
studies the link between personal habits and health. "We now know that's
not true." (See "What
Research Shows" for citations of the key research demonstrating the benefits
of walking.)
But all of the research fails to answer the question of how something so
simple can have such salutary
effects.
As soon as you take that first step, a host of metabolically significant
events is set in motion inside your
body.
According to Greg Heath, lead scientist in the CDC's physical activity
and health branch, early in your
walk your adrenal glands begin secreting adrenaline, which gets into your
bloodstream and signals your
heart to beat faster and causes your blood pressure to go up. The heart
then begins to pump more
blood away from the chest and into the muscles of the limbs you're using
to get yourself down the street.
As a result, blood vessels in the arms and legs begin to expand as they're
fed more nutrients and oxygen
by the blood.
As your heart rate climbs, you're taking more breaths per minute, sometimes
increasing your oxygen
intake to 10 times the amount you'd be taking in if you were sitting still.
As the muscles receive more
blood, they begin to use up carbohydrates and sugar starches they've stored.
Metabolism -- the
process by which the body breaks down materials and converts them to fuel
-- speeds up. As a result,
so does digestion.
All this activity causes the brain to release endorphins into the bloodstream.
Endorphins, which have
chemical properties similar to opium, are responsible for blocking pain
and ushering in that cozy sense
of well-being you feel as soon as your walk ends. Additionally, exercise
causes the brain to release an
abundance of the neurotransmitter serotonin, which works to elevate mood.
And that's all during the course of one walk. If you walk regularly, you
can
expect exponentially more benefits. Explains JoAnn Manson, director of
preventive medicine at Harvard's Brigham and Women's Hospital, your
heart muscle will grow stronger and better able to deliver more oxygen
to
the body during periods of rest. The lungs, capillaries and vessels along
the
oxygen transport pathway will expand to handle more capacity, bringing
more oxygen to more parts of the body more often, a process that has
been linked to reductions in risk of cardiovascular disease.
Blood pressure drops within 24 to 48 hours of exercising, and will stay
down with continued exercise.
The risk of blood clots also drops and stays lower if you keep the walking
up. Circulation improves,
which makes digestion more efficient. The body becomes better at getting
glucose into the muscles
where it's needed, thus smoothing out blood sugar levels and helping the
body process fat. The body
gets better at converting fat into energy, so you lose weight more easily
than with dieting alone.
In addition, regular walking, especially the more vigorous sort, increases
lean muscle mass, which
consumes more energy than a similar amount of fat, thereby helping you
maintain a healthy weight.
Regular exercise can also help you sleep better, which in turn delivers its own set of health benefits.
All of which is to say, once you get going with a regular walking program,
your body becomes a kind of
self-improvement machine.
As You Like It
Walking sessions can be toned down or ginned up, depending on your health
goals and physical
abilities.
To raise your cardiovascular fitness level, you need to elevate your heart
rate to 60 percent to 80
percent of its maximum. This can usually be accomplished by walking briskly,
as if you are late to an
appointment. Those seeking to lose weight should look to keep their heart
rates less elevated but for a
longer time. (See suggested four-week walking programs on Page F5.)
To equal the aerobic workout that runners get, walkers need to go a little
farther a little more often than
runners. A recent Cooper Institute study showed that walkers had to exercise
for 40 minutes four times
a week to equal the aerobic benefit runners got from running for 30 minutes
three times a week.
"That's a real good tradeoff for most walkers," said Johnson.
Or you could go the 10,000 steps route. Barbara Moore, president of Shape
Up America, founded in
1994 by former surgeon general C. Everett Koop to provide science on the
benefits of exercise, says
10,000 steps a day is a good goal to shoot for if you're trying to get
fit.
Spring for a pedometer (see "How Much of This Stuff Do You Really Need?"
Page F3) and clip it on
your waist from morning to bedtime. Moore says a broad body of studies
has shown that walking
10,000 steps a day -- either via 10-minute bouts here and there or through
lengthy loops around a track
or your neighborhood -- is associated with a range of health benefits.
Those 10,000 steps will translate into a different distance for each person,
but for Moore they equal
about five miles. The typical office worker, she says, averages 2,500 to
5,000 steps a day. For those
who are daunted at the prospect of doubling their steps and maybe doubling
them again, Shape Up
America offers details on starting a 10,000-step program (www.shapeup.org).
For the vast majority of Americans who are not faced with a prohibitive
disability, walking is the best choice as a regular form of physical activity,
says Mark Fenton, whose roles as host of the PBS series "America's
Walking," former coach of a national racewalking team and author of "The
Complete Guide to Walking for Health, Weight Loss and Fitness" (The
Lyons Press, 2001) make him America's reigning guru of walking.
Particularly for the 60 percent of Americans carrying more poundage than
they should, walking is a safer choice than running, said Fenton. The reason:
impact. A walker lands
with only one-fifth the force of a jogger or an aerobiciser. Besides, adds
Jon Schriner, medical director
of the Michigan Center for Athletic Medicine and a spokesman for the American
College of Sports
Medicine, so many people already have problems with their hips, knees and
ankles that they couldn't
run very far or very often if they tried.
Fenton adds that walking is something you can do even when your life circumstances
have been
changed -- when you're pregnant, injured or older. Most people remain capable
of walking throughout
life, even if they have to do it more slowly or with assistance. (Of course,
some people do lose the
ability to walk due to accidents, disease or infirmity.) This makes it
something people are likely to stick
with: Only 25 percent of those who walk for exercise quit, estimates the
Cooper Institute, compared
with 50 to 60 percent of people who start other exercise regimens.
If all these reasons seem too self-centered, try this one: civic activism.
A community that has plenty of
people walking around, says Fenton, is usually a safe community and an
economically vibrant one, as
walkers tend to keep their eyes open and partake in a bit of retail along
the way. It's also full of the kind
of social interaction many other communities lack, as chance encounters
lead to conversation and
greater awareness about the other people in the area.
Which is to say, in addition to everything else, walking can make the world
a better place. But don't
worry about that for now. Look up. See the nearest door leading outside?
That's your first target.
Suz Redfearn is a regular contributor to the Health section.
© 2002 The Washington Post Company