Fitness fanatics, beware: A new Japanese study suggests that women who exercise a lot and eat a heart-smart diet high in so-called "good fats" may reach menopause more quickly, putting them at risk for a host of health problems.
The researchers tracked 3,115 women for 10 years, collecting data on their exercise and eating habits. They found that the women who spent eight to 10 hours a week exercising were 17 percent more likely to start menopause early, compared to women in the study who weren't exercising. Those who ate plenty of polyunsaturated fats (found in fish and vegetable oils) were 15 percent more likely to hit menopause early, compared to women who consumed less of those oils. "Total fat, other types of fat, dietary fiber, soy isoflavones, and alcohol were not associated with the onset of menopause," Dr. Chisato Nagata of Gifu University and his colleagues wrote in the study.
There are pros and cons to early menopause, doctors say. On the one hand, women who are in menopause have lower estrogen levels, which can reduce their risk of breast cancer. But on the other hand, menopausal women are more likely to develop heart disease and bone-density loss; they're also more likely to experience sexual dysfunction. And, of course, no ovulation and low estrogen levels means no fertility.
Experts are quick to point out that Nagata's research does not prove that exercise causes early menopause, it just says that the two may be associated.
"I wouldn't want women to be concerned that they would be at higher risk of cardiovascular disease or osteoporosis if they make lifestyle modifications," the president of the North American Menopause Society, Dr. JoAnn E. Manson of Harvard Medical School, told Reuters. "The benefits far outweigh any risks."The study, published in the journal "Menopause," does raise a few other questions. The researchers focused on women who were 36 to 55 years old at the start of the 10-year-study, but according to the North American Menopause Society, menopause usually starts between the ages of 41 and 55. More than half of the women in the study-1,790 of them-reached menopause while the study was still going on. Did some of them really stop ovulating early, or were they on target for menopause regardless of their exercise regimens? And other studies have linked excessive exercise to irregular menstrual cycles-which usually leads to a later onset of menopause. What about those women?
The real focus, Manson says, should be on the fact that strenuous exercise can lower a woman's estrogen levels, and lower levels of that particular hormone can reduce the risk of certain types of cancer.
"Regular physical activity and regular heart-healthy patterns are advisable for reducing the risk for several hormone-related cancers and osteoporosis," she told Reuters. "It's a modest effect, but it matters."
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