On the Road Again.

Anna didn't need the usual urging from nurses to walk the hospital corridors following cancer surgery. She was eager to begin, since walking had always been part of her life. Once home, she rebuilt her stamina by increasing her walking distance one day at a time.

Anna was doing more for her body, though, than building stamina. She was also lessening her chances of developing the depression that affects many who experience life-threatening medical conditions.

Vice President Dick Cheney and Larry King are among those who credit walking with helping to get them back to work following heart attacks and bypass surgery.

Walking, though, is not just beneficial for "after the fact" conditions. The ongoing Nurses' Health Study, involving 72,488 female nurses aged 40 to 65, shows walking briskly or with a good stride can lower the risk of stroke compared with an average or casual pace, and the same study shows that walking also reduces the risk of diabetes in women. Several other studies have already shown that exercise can reduce the risk of coronary heart disease. Also, the Journal of Obstetrics and Gynecology reported in October 2000 that exercise, such as walking, decreases the chance for certain types of ovarian cancer.

Walking also increases muscle strength; improves bloodflow; reduces the risk of hypertension; lessens lower back pain; increases the amount of good cholesterol; helps in weight loss; and since it is a weight-bearing exercise, it helps in maintaining strong bones.

Just as important, walking affects how we think. Even if individuals haven't walked during their younger years, small increases in exercise, such as walking, improve mental fitness, particularly for "executive control functions of the brain," involved in the ability to plan, coordinate, and schedule activities, says Arthur F. Kramer, cognitive neuroscientist at the University of Illinois. Participants at the university were randomly assigned to a walking program or a regimen of stretching and muscle toning. Walkers eventually Were completing an hourlong walk three times a week.

After six months the walkers' ability to switch tasks improved by 25 percent, while the toning and stretching participants showed little improvement. Kramer says that a possible explanation is that walking improves cardiorespiratory fitness, which, in turn, improves blood flow to the frontal and prefrontal areas of the brain, which control the executive function processes.

Also on the mental front, walking helps to overcome severe depression in some people on a par with antidepressant drugs. One of the theories is that exercise such as walking increases brain chemicals such as serotonin and norepinephrine, the same as antidepressant medications. Antidepressants may initially work more rapidly, but walking for 16 weeks has proved as effective in reducing depression and may work better in the long run to keep the symptoms from returning, says Duke University Medical Center psychologist James A. Blumenthal.

Blumenthal considers walking an alternative to drugs for certain people, and says it might be tried as a first line of treatment, rather than starting a person on antidepressants right away. "But it's different from writing a prescription. Other things could also contribute," he says.

Participants in the Illinois study had already been diagnosed with major depression, and had volunteered, which boosted their self-confidence, since it gave them a measure of control over their own body. Volunteers have also been more likely to stick with an exercise program than sedentary nonvolunteers. The walking was done in groups, providing support, which also helped to reduce depression.

Another reason walking might work is that it reduces stress, which often contributes to depression, even if it's mild, according to the National Institute of Mental Health.

Since the aged tend to have high levels of depression, several studies have been conducted to find out if exercise helps. It does, but removing aging stereotypes along the way is a plus. Studies at Harvard Medical School show that older people who receive subliminally delivered positive words about being old, such as "wise," "astute," and "accomplished," increase their walking speeds by 9 percent. Those who receive negative words about aging, such as "senile," "dependent," and "diseased," maintain the same walking speed they begin with.

The studies are important because a person's usual walking speed is a common measure of overall fitness, which tends to decrease 9 to 30 percent with advancing age, says Jeffrey Hausdorff, assistant professor of medicine at Harvard Medical School.

Just as important, though, according to Hausdorff, is "the role of self-expectations, attitudes and stereotypes on function. We all are aware how these things can influence our psychological state. Our studies suggest that they also influence our physiologic function. While a better attitude and positive outlook won't solve all problems, it may help to improve function."

He cautions, though, that several factors contribute to the decline in walking performance, including genetics, the environment, lifestyle, previous activity levels, and nutrition.

"Some walking changes with aging, such as those resulting from neurodegenerative disease, may not always be preventable. Nonetheless, routine participation in appropriate exercise and walking programs will significantly reduce the risk of later age-associated declines in walking performance," Hausdorff says.

Maintaining speed, though, is not the goal for all. Fibromyalgia patients may benefit more from moderate walking two or three times a week, rather than a strenuous regimen, says Barbara Meyer, assistant professor, Department of Kinetics, at the University of Wisconsin.

"Although the individuals in our study did not have decreased pain with exercise, they did have improved function," Meyer said. She also noted that it took six months of regular low- to moderate-intensity walking before any improvement in function. At three months the women had not improved.

The mounting evidence that walking can boost mental and physical health for all age groups is only the beginning for couch potatoes, people who figure they don't have time, or those who don't think their neighborhoods are worth walking in. Some communities have gotten into the act by trying to build public awareness of walking's health benefits. Missouri has proven a leader in promoting "walking trails" in rural communities where few sidewalks, shopping malls, or other affordable places to walk are available.

Ross C. Brownson, professor of epidemioloy at St. Louis University School of Public Health, who is involved in building coalitions with community leaders to build the trails, says that "even the previously inactive have taken to trail walking, especially in areas where previously none existed." Many of the most effective trails have been established by volunteers, and especially by church groups in their rural communities. To promote use, the churches sponsor events at the trails open to everyone, he says.

What Missouri researchers have discovered so far is that women using the trails are more than twice as likely as men to report that they have increased the amount of walking since they began; that lower income groups were more likely to increase walking because of trail use than higher income persons; but that, overall, the trails increase activity levels for a wide swath of people.

"Up to 40 percent have used the trails in their areas. It's promising because those are the groups who tend to be inactive. One number we have used a lot is that 55 percent said they had increased the amount of time they walk since they began using the trails.

"What we found is that if we build them, they will come," says Brownson.

Anna, Dick Cheney, and Larry King clearly knew what they were doing when they walked. They joined the approximately 20 million people in the United States, age 25 and older, who walk at least twice weekly, and the number keeps increasing yearly.

Rita Robinson is a freelance writer from Big Bear City, California.