THURSDAY, Jan. 3 (HealthDay News) -- Exercise is not a cure for hot flashes, but it does help postmenopausal women cope with stress, anxiety and depression, a Pennsylvania study has found.

The researchers had hoped to prove that exercise could be a less risky alternative to hormone replacement therapy for women suffering from hot flashes, said study author Deborah B. Nelson, a professor of public health and obstetrics and gynecology at Temple University in Philadelphia.

But, she added, "we didn't find a relationship between physical activity and hot flashes."

However, the study did find that more exercise led to lowered levels of perceived stress. "The level of anxiety, stress and depression were significantly lower among physically active, postmenopausal women compared to postmenopausal women in the lowest" level of physical activity, the researchers reported in the January issue of Medicine & Science in Sports & Exercise.

Still, the results are significant, because the hot flashes women experience as they go through the menopausal transition are often a temporary problem, Nelson explained. Women live a long time in postmenopause, which can be a period when they may struggle with stress, anxiety and depression, she said.

The study was conducted over eight years, beginning in 1996-1997. Nelson's team studied 380 women, average age 42, in the Philadelphia area who walked between 15 minutes and 90 minutes daily for up to five times a week.

"We know that physical activity is helpful in reducing anxiety and stress. What was surprising was that it wasn't a lot of physical activity. It was mainly walking," Nelson said. "It is encouraging that it's something women can incorporate into their daily routine. The next question is would it be even more helpful if they were involved in a higher level of physical intervention."

At the beginning of the study, all of the women were not menopausal. By the end of the study, more than half had experienced hot flashes.

Paradoxically, the researchers found that a mid-level of exercise appeared to make symptoms worse for some women in the late transitional stage, when menstruation may cease for three to 11 months and hormones hit new highs and new lows. After analyzing the data, the investigators concluded that the intensity of the symptoms was more the result of wide-ranging fluctuations in hormones rather than the physical activity promoting any symptoms.

Black women appeared to have more hot flashes than whites, but that could be because as a group, they were heavier and had lower hormone profiles, Nelson said. Physical activity also seemed to provide greater stress reduction for the group of black women. Because they were slightly heavier and smoked more, this level of physical activity was especially helpful to them, Nelson said.

It's not surprising that exercise doesn't help hot flashes, said Dr. Nieca Goldberg, medical director of the Women's Health Program at New York University Medical Center, New York City. "The reason why there are hot flashes is because the brain's center for temperature is altered by the lower levels of hormones," she explained. Since exercise raises the body's temperature, it's logical that it wouldn't make women experiencing hot flashes feel any cooler, she added.

Other research has found that exercise has "no influence over the number of hot flashes, but it's shown that women cared less about having them," which goes along with the psychological benefits of exercise, Goldberg said.

Dr. Hugh Taylor, a Yale University professor of reproductive endocrinology, noted that women in different cultures have very different attitudes toward hot flashes even though they have just as many as American women. Asian women, for example, "just seem to deal with them better. Maybe this is one answer why: exercise, more physical activity."

The psychological benefits of exercise for postmenopausal women are an important finding, Taylor added. "A lack of estrogen does lead to an increase in stress, anxiety, and depression," he explained.

More information

There's more on menopause at the National Women's Health Information Center.

SOURCES: Deborah B. Nelson, Ph.D., assistant professor, public health and obstetrics and gynecology, Temple University College of Health Professions, Philadelphia; Nieca Goldberg, M.D., medical director, Women's Health Program, New York University Medical Center, New York City; Hugh Taylor, M.D., professor and chief of reproductive endocrinology and infertility, Yale University School of Medicine, New Haven, Conn.; January 2008 Medicine & Science in Sports & Exercise

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