If any woman needs motivation to exercise, lose excess weight and improve her lifestyle, she should listen to Dr. Anne McTiernan of the Fred Hutchinson Cancer Research Center.

McTiernan is a prolific researcher into the role that exercise seems to have in reducing the risks of contracting breast cancer and possibly staving off recurrence. While health experts don't completely understand the relationship between fitness and the disease, an increasing number of studies are bearing out the belief that there is one.

Most epidemiological studies have found that women who exercise even moderately, say brisk walking or jogging, for more than three hours a week have a 30 percent reduced risk of getting the cancer.

Women who are overweight or obese after menopause tend to have high levels of estrogen, which promotes the growth of cancer cells, and are almost twice as likely to get the disease as their thin counterparts, studies suggest.

There is a benefit other than simply losing weight, of course. People who exercise more tend to follow healthier lifestyles through nutrition, sleep and stress management. But medical researchers such as McTiernan are tracking down specific answers as to why.

In the meantime, get moving, she and other researchers urge.

"By doing something, you can affect your biology," she says. "It's never too late to start."

There is likely more benefit the more you exercise, she says, but moderate exercise will probably make a difference. Walking is an important way to begin. McTiernan implores women not to scrimp on shoes. Nothing stops a walking regimen in its tracks faster than sore feet.

The new Fred Hutchinson Cancer Research Center recently opened on South Lake Union. A gymnasium has been installed in the basement and is used by many of the research subjects McTiernan follows. The space contains treadmills, elliptical trainers and stationary bicycles, and has a separate room where researchers can take baseline tests on a participant's fitness. In a dining area, research subjects eat specially prepared diets as part of a nutrition study.

Fred Hutchinson is participating in a multi-site study into ways to decrease the chances of recurrence in women who already have gotten the disease. The study's hypotheses are that a better prognosis is associated with diets high in vegetables, fruit and fiber but low in fat; high levels of physical activity; and low abdominal fat.

Results of a massive and long-term study conducted elsewhere show strong evidence that women who exercised after diagnosis reduced their risk of dying from the disease by between 25 and 50 percent, depending on how active they were.

Most of the women walked as their form of exercise. Those who put in one to three hours of leisurely walking lowered their risk of dying from breast cancer by one-quarter when compared with sedentary women. Those who walked between three and eight hours a week cut their risk in half.

McTiernan also has co-written an informative book titled "Breast Fitness" in which she discusses an exercise and health plan.

Where you carry your fat may be critical, she says. The Iowa Women's Health Study found that women with "apple" shapes, in which fat accumulates around the waist and abdomen, are at higher risk than those who put on weight mostly around thighs and hips.

The book offers ideas to help women stick with their exercise program, such as being flexible and realistic, and devising a specific goal, getting friends to help, and monitoring progress. A number of exercises are included, as are some sample ways to set appropriate goals. For instance:

• If you've never exercised, start with a walking program.

• If you've exercised before but stopped, get into an aerobics class three times a week.

• If you're exercising but want to do more, increase your schedule, say from jogging three times a week to five.

• If you're happy with your exercise program but need motivation, consider running a marathon.

To join a study: Postmenopausal women who would like information about participating in future exercise, nutrition or medication-related breast cancer-prevention studies at Fred Hutchinson Cancer Research Center may call 206-667-6444.

Simple changes can be life-savers

Fred Hutchinson researchers have found that simple lifestyle changes can go a long way toward detecting cancer earlier, when it is treatable, and possibly preventing it. Here are some of their discoveries:

• Scheduling a mammogram during the first two weeks of the menstrual cycle, when breast tissue is less fibrous and dense, can improve the accuracy of such exams.

• Drinking at least five glasses of water a day is associated with lowering a woman's risk of colorectal cancer by more than 50 percent.

• Eating at least three servings of vegetables a week — especially the cruciferous kind, such as broccoli and cabbage — is associated with lowering a man's risk of prostate cancer by nearly half.

• Taking a multivitamin daily for 10 years is associated with lowering the risk of colorectal cancer by half.

Richard Seven is a Pacific Northwest magazine staff writer. He can be reached at rseven@seattletimes.com.