(Cambridge, Mass.) - Becky Boock has always been a dedicated athlete, delighted in the thrill of the race. An old competitive corridor and swimmer, the 19-year Canadian races in at least three triathlons every summer. Now she has an additional reason to continue moving: Boock recently lost her mother to breast cancer.
"Exercise is a way out and a form of prevention for me," she says. "I can only hope that my healthy lifestyle help me get safe." Boock is not alone in this hope.
Even women who have not lost a relative to breast cancer often fear this disease more. And until recently, experts were not able to offer solid evidence for those who wonder if lifestyle factors, such as exercise, can reduce their risk.
But now this is changing. After years of conflicting discoveries, a new consensus is emerging. It is a very good news for women who are exercising, as well as for anyone who is looking for a new reason to motivate: regular exercise, it seems, can really cut the chances of having breast cancer.
The last study, published in the January 19 issue of the National Cancer Institute magazine, found that active women were about 30% less likely to obtain the disease. In last October, researchers at Harvard University published discoveries of the health study of large-scale nurses showing that regular exercisers cut their risk by 20%. "If you take all data on balance, there is a moderate reduction of risk," says Beverly Rockhill, Ph.D., the main author of Harvard's study.
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Data have not yet pointed in that direction. In fact, in an earlier analysis of the data of the study of nurses, Rockhill and his colleagues were unable to show that the exercise offered any shield. "We found no protective effect," Rockhill said at the time. Other researchers cited in a review article published in the January 21, 1998 issue of the magazine of the National Cancer Institute discovered that exercise reduced risk before - but not later - menopause. Still others quoted in that article found precisely the opposite. And at least one revised study showed that exercise raised the risk.
In many ways, exercise can reduce the amount of estrogen that the body produces. Young girls who are very active can avoid the beginning of menstruation. Adult women exercising even moderately are likely to ovulate less regularly, although their periods may continue. Postmenopausal women whose ovaries no longer improve the hormone still exposed to a version of estrogen produced by fat stores; Exercising enough to hold weight down and convert fat into muscle should reduce the estrogen exposure of older women and therefore your risk, too.
What remains a bit obscure is exactly how much to exercise a woman needs to do and at what time in your life she needs to do this. More seems to be better, but some is better than none. Bernstein's study, for example, discovered that women who exercised four hours a week have more protection than those who worked for only two.
For now, most experts suggest that women expecting to lessen their chances of breast cancer follow the recommendation of the general surgeon at least 30 minutes of moderate activity - as the fast walk - a day. And, of course, they should continue to get regular exams and mammograms, which are still the best protection of all.
As for Becky Boock, she will be participating in this spring in a city race that means more to her than any other: a 10k mother relay that will raise money for breast cancer research. The organizers dedicated the race to the Boock's mother.
Tinker ready is a health writer and freelance sciences based on Cambridge, mass. His work regularly appears on Boston Globe and nature medicine.
