Signs Say To Keep Walking

Taking a regular, brisk stroll may be the best defense against heart disease, cancer, diabetes and more

March 16, 2007|By Regina Nuzzo | Regina Nuzzo,Los Angeles Times

Remember fitness in the 1970s? All those aerobics classes, leotards and sweatbands, the endless jogging and velour track suits? Got to crank up that heart rate to 90 percent of maximum, experts told us. No pain, no gain.

But today a new, easygoing message reigns: Leave the spandex at home - you don't have to sweat or even change your clothes. Simply take a walk. Aim for least 30 minutes of activity on most days of the week, experts advise. Break it up into a few brisk-walking "snacks," if you prefer. Vigorous exercise is great, they say, but don't feel pressured.

What happened? Did experts notice that we weren't living up to their high-heart-rate expectations and decide, with resignation, to lower the bar? Or has the science of exercise evolved into something more subtle than, say, Richard Simmons' shorts?

Yes, and yes.

Public health officials are indeed desperate for us to get off our duffs, and they prefer minimum guidelines that don't scare us off. But research during the past decade has also shown that physical activity doesn't need to be vigorous to be beneficial.

Brisk walking can help prevent cardiovascular disease, colon cancer, osteoporosis and diabetes, researchers say. Those who suffer a broader set of disorders - including breast cancer, depression, cognitive decline and sexual dysfunction - might also benefit from regular strolls around the block.

"Walking may be as close to a magic bullet as you'll find in modern medicine," says Dr. JoAnn Manson, professor of medicine at Harvard Medical School. "If there was a pill that could lower the risk of chronic disease like walking does, people would be clamoring for it."

Walking is the ultimate no-fuss exercise. You don't need training or equipment (though plenty of books and gadgets are available to help). Walking can get you from point A to point B in an earth-friendly, non-gas-guzzling way. It can be fine-tuned to your fitness needs - suitable for just-off-the-couch potatoes and adrenaline junkies alike.

And here's another big plus: Walking is fun, offering up an eye-opening view of a world normally glimpsed only as a car-window blur.

Walking's path

The road to modern exercise science started in the 1950s, when researchers found that London bus drivers who sat behind the wheel all day tended to suffer more heart attacks than their co-workers who walked around the double-deckers punching tickets.

Researchers quickly homed in on a good measurement of physical fitness - the amount of oxygen a body was capable of delivering to muscles during all-out physical exertion. They promoted vigorous exercise as the key to good health.

The first exercise guidelines from the American College of Sports Medicine, released in 1975, encouraged people to exercise vigorously and often, at 70 percent to 90 percent of maximum heart-rate reserve.

(For a rough approximation of the upper range, subtract your age from 220 and multiply by 0.9 - that's about 162 beats per minute for a 40-year-old.)

Ten years later, only 20 percent of Americans met these standards - and 40 percent were still completely sedentary.

Then came a new era in exercise. Evidence was amassing that less-than-punishing exercise had its health benefits, too. In 1995 the American College of Sports Medicine and the Centers for Disease Control and Prevention came up with a brand-new exercise plan: Accumulate at least 30 minutes of moderate physical activity - walking, gardening or golfing, for example - on most days of the week.

The U.S. surgeon general, the National Institutes of Health and the World Health Organization soon followed with similar guidelines.

The new buzz: bite-sized pieces of "physical activity." Brisk walking and similar activities - which gurus once brushed off as too wimpy to do much good - were linked in large, long-term studies to lowered risk for heart disease, diabetes, high blood pressure, colon cancer, osteoporosis, anxiety and depression.

How hard people exercised seemed to be less important than how long they were active. And, it seemed, you didn't even have to do all that exercise at the same time: Intermittent activity was as beneficial as long bouts of exercise.

"It was a bit of a revolution in the world of physical activity," says Steven Blair, professor of exercise science at the University of South Carolina and senior editor for the Surgeon General's report.

Today, even more scientific evidence has stacked up - including some gold-standard randomized clinical trials - showing the benefits of moderate exercise for other disorders, such as Alzheimer's disease, stroke, cognitive decline, breast and prostate cancer and erectile dysfunction.

Some of the conclusions are still surprising, and still debated. Not only is brisk walking better for your health than, say, dozing in front of the TV (no argument there), but apparently it's also nearly as good as spending that time jogging.

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