Practically every morning at 7:45, Anna May Martin hits Marley Station Mall with a neighbor. Not to shop -- it's far too early for that. Instead, the 67-year-old Glen Burnie resident goes to walk.
Striding for 45 minutes or so around the shopping center energizes Ms. Martin, who began the regimen three years ago to control her high cholesterol. "If I were home, I'd just be doing housework or sleeping later," said the peppy homemaker. "This way, I feel really refreshed and alert when I get back."
Ms. Martin has plenty of company. Thanks to its reputation as a low-injury, low-cost activity which yields many health benefits, walking has surged ahead of swimming and bicycle riding to become the most popular exercise activity in the country, according to a survey published last July by the National Sporting Goods Association. About 71.5 million Americans, many them senior citizens, now walk regularly to improve their cardiorespiratory fitness and muscle tone, as well as to lose weight.
Now, the recent release of a study showing that you don't have to move quickly to gain significant health benefits from walking may prod even more people to head to their local malls and tracks.
The study, published last month in the Journal of the American Medical Association, showed that women who walked a mile in 12 minutes and those who completed the distance in 20 minutes had the same 6 percent increase in high-density lipoproteins (HDL) -- the "good" cholesterol.
Past research has shown that an increase in HDL cholesterol leads to a significant reduction in the risk of coronary disease, according to Dr. John Duncan, an author of the report.
"We concluded that intensity does not seem to be as important in increasing HDL cholesterol as walking regularly," said Dr. Duncan, associate director of the Department of Exercise Physiology at the Dallas-based Cooper Institute for Aerobics Research. The 24-week study, which evaluated 102 women, was conducted at the Cooper Institute.
On the other hand, those who stepped up their strides did gain extra benefits. Women who walked a 12-minute mile burned off about 53 percent more calories than 20-minute milers -- 535 to 960 calories per 3-mile walk, rather than 300 to 360. They also increased their cardiorespiratory fitness levels by about four times that of 20-minute milers.
Still, the study may have an impact on those who do no exercise, according to Dr. Kerry Stewart, head of the Cardiac Rehabilitation and Prevention Programs at Francis Scott Key Medical Center. "This may encourage people who otherwise wouldn't walk, because they can't walk briskly, to do it on a regular basis," said Dr. Stewart. However, he added that he'd like to see the study substantiated with more research.
The concept of low-level activity may appeal to a far larger population than the vigorous forms of exercise promoted in the 1970s and 1980s Dr. Duncan said.
Nonetheless, this study and others like it is changing the ways doctors and exercise physiologists treat their clients. Rather than direct someone to try to achieve a maximum heart rate while walking, David Petrie, an exercise physiologist who heads the Human Performance Lab at the Sports Medicine Center of Union Memorial Hospital, now eschews such instructions.
"I just tell people to get out there and walk, and not to worry about the other stuff," said Mr. Petrie, who designs exercise programs. "You can slouch along, and what you're doing is still more than someone who's sitting down."
In previous years, Mr. Petrie sang a different song. At speaking engagements he would "tell people that unfortunately, their little lunch-hour walk to the Rusty Scupper wasn't doing anything," he remembered. "That's always been my patented thing. But," he shrugs, "I was wrong."
Apart from encouraging the sedentary to take up walking, the study may also relieve some guilt among those who won't win any Olympic medals for quick walking.
"It definitely makes me feel better to know that just doing what I'm doing is as good as the people who are racing around and trying to go fast," said Margy Klein, a 33-year-old Columbia travel agent who walks every weekend at a steady but unspectacular pace. She usually finishes 6 miles in about two hours.
But not everyone subscribes to the concept of strolling. Ever since it was founded 81 years ago, the Walkers Club of America, a 25,000-member non-profit organization, has advocated brisk walking. The release of the Cooper Institute's study hasn't caused it to change its pace.
"We feel that fast walking helps fitness and endurance in ways that slow walking can't," said Howard "Jake" Jacobson, executive director of the Commack, New York-based organization, which works to promote walking. Mr. Jacobson pointed out that, as the Cooper Institute study showed, those who keep up a rapid pace burn off calories much more quickly than those who mosey along. They also improve their cardiorespiratory fitness at a quicker rate, and build up their muscles faster.