You’ve heard it before: getting regular exercise is crucial for living a long, healthy life. But scientists are discovering that staying active has even more benefits than previously discovered: it could help prevent breast cancer. Keep reading to discover how exercise can reduce breast cancer risk–even if you’ve been diagnosed with it previously.
Can exercise reduce the risk of breast cancer?
A number of studies over the past decade have highlighted the benefits of consistent physical activity as a potential defense against breast cancer. In fact, a 2016 review–which pooled data from 38 different studies–found that women who frequently exercised had a 12-21% lower risk of breast cancer than those who rarely got moving.
Exercise offers these protective benefits to premenopausal and postmenopausal women. As an added perk, women who ramp up their physical activity post-menopause might lower their breast cancer risk even more than those who are only moderately active, according to some studies.
How does exercise prevent breast cancer?
Exercise is a powerful tool when it comes to maintaining a healthy weight. This is why many experts have hypothesized that it’s one of the best ways to prevent breast cancer, as obesity can significantly increase a woman’s risk for this disease after menopause.
If diagnosed as obese, a woman faces a 30% higher likelihood of dying from breast cancer in subsequent years. The American Cancer Society’s 2019 figures link the growing rates of hormone receptor (HR)-positive breast cancer (the most common kind) to the rising prevalence of excess body weight.
But the story of exercise and its role in reducing breast cancer risk doesn’t end there. A recent Danish study illuminated even more facets of this connection–particularly for those who’ve survived breast cancer and are concerned about recurrence.
New research on exercise to reduce breast cancer risk
In one study spearheaded by Dr. Pernille Hojman at Copenhagen University Hospital, researchers took blood samples from two groups: healthy women and those undergoing chemotherapy after breast cancer surgery. All participants were part of a six-week exercise program, involving two hours of moderate to intense exercise per day.
After each workout session, researchers obtained participants’ blood serum (a cell-free part of the blood; it’s the liquid that remains after blood has clotted) and noticed a remarkable trait: physical activity appeared to weaken the growth of specific breast cancer cells in lab tests by as much as 10-15%.
Researchers also found that epinephrine, a hormone that rises during exercise, played a pivotal role. For instance, when MCF-7 cells (a type of breast cancer cell) exposed to this post-exercise serum were injected into mice, their ability to form tumors was drastically reduced.
45 percent of mice receiving the cells exposed to serum obtained after exercise developed tumors compared with 90 percent of mice receiving cells exposed to serum obtained at rest. Specifically, the hormone seemed to activate a known tumor-inhibiting mechanism called the Hippo signaling pathway in these cells.
“Although these data suggest that it might be optimal for women with breast cancer to exercise at a moderate to high intensity, further studies are needed to confirm this,” Hojman cautions. “Women who have been diagnosed with breast cancer should consult a doctor and make sure health is managed before embarking on an exercise program.”
Hojman’s team also noted that two types of breast cancer cells have been used in studies on the ability of exercise to prevent breast cancer: MCF-7 cells, which respond to hormones, and MDA-MB-231 cells, which don’t. Research suggests that exercise might be more effective at preventing the return of hormone-responsive cancers (like MCF-7). Another factor may be related to genes.
What type of exercise is best to prevent breast cancer?
While any physical activity is beneficial, most research has focused on women who participate in moderate to intense cardiovascular exercises such as:
- Walking briskly
- Running
- Bicycling
- Rowing
- Swimming
For maximum benefits, the American Cancer Society recommends 150-300 minutes (2½-5 hours) of moderate activity or 75-100 minutes (roughly 1-2 hours) of more vigorous activity each week. You can split this total up into smaller, daily workouts. But don’t forget that even lighter activities such as gardening or mowing the lawn offer great benefits, too.
Scientific studies continue to highlight the ability of exercise to prevent breast cancer recurrence. But remember that cancer is a complex disease–so staying active is only one piece of the puzzle.
As we await further research, combine regular physical activity with other healthy habits like eating a balanced diet, limiting alcohol consumption, and undergoing regular breast exams to reduce breast cancer risk and enhance your well-being.
References:
https://academic.oup.com/aje/article/181/12/944/91671
https://pubmed.ncbi.nlm.nih.gov/27601139/
https://www.cancer.org/cancer/latest-news/get-moving-to-help-reduce-your-risk-of-breast-cancer.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071977/
https://pubmed.ncbi.nlm.nih.gov/26687833/
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https://pubmed.ncbi.nlm.nih.gov/20975025/
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https://www.cdc.gov/physicalactivity/basics/adults/index.htm#:~:text=Each%20week%20adults%20need%20150,Physical%20Activity%20Guidelines%20for%20Americans.&text=We%20know%20150%20minutes%20of,do%20it%20all%20at%20once.
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