The average woman has a one in eight chance of developing breast cancer over a lifetime. Those aren’t insignificant odds, although the risk of dying of heart disease is still higher. Fortunately, a healthy lifestyle helps to mitigate some of the risk. In fact, studies suggest that 25% to 30% of breast cancers can be prevented by leading a healthy lifestyle. That’s encouraging!
What are the lifestyle factors that can lower your risk? How about diet? Eating more fruits and vegetables reducing consumption of red and processed meats are associated with a lower risk of breast cancer in some studies. Exercise also seems to have a protective effect. In fact, a review of 67 studies and articles found physical activity was the most important factor associated with a reduction in breast cancer recurrence.
Another factor is weight gain. Gaining more than 10% of body weight after a breast cancer diagnosis is linked with higher mortality from breast cancer. Being overweight or obese or gaining more than 20 pounds during adulthood is also a risk factor for breast cancer. For women who have never had breast cancer, staying physically active seems to lower the odds of developing the disease in the first place.
Exercise and Breast Cancer risk
What type of exercise offers the most protection against breast cancer? Is it stretching, yoga, long-distance, running, or strength training? A new study suggests that high-intensity exercise may offer the most benefits. As you know, intense exercise ramps up the sympathetic, or fight or flight, portion of your nervous system. During periods of stress, including high-intensity exercise, the adrenal glands secrete a catecholamine called epinephrine. It’s epinephrine that speeds your heart rate and diverts blood flow to your muscles, so you can react quickly to whatever is threatening you. To get the most epinephrine release, you need to exercise hard, enough to cause breathlessness.
What researchers from Denmark found is that epinephrine, as well as other catecholamines, stymy the growth of cancer cells. Research in this area shows that intense exercise turns on a well-characterized tumor suppressor pathway called the Hippo signaling pathway. In fact, when cancerous cells were exposed to epinephrine, their growth slowed by 50%.
No doubt, an intense HIIT workout boosts the release of epinephrine – and if epinephrine slows tumor growth, that’s beneficial! What’s more, researchers found that a single, intense exercise session released enough epinephrine to block the growth of breast tumor cells. Of course, more research is needed to confirm these findings. Yet, we know that exercise seems to protect against breast cancer, particularly estrogen-receptor positive breast cancer, the most common kind.
Other Ways Exercise May Lower the Risk of Breast Cancer
Scientists also believe that exercise could lower breast cancer risk in another way. Women who work out tend to metabolize estrogen differently. Your liver breaks down estrogen into two main types of estrogen metabolites, 2-OHE1 and 16-alpha-OHE1. A higher ratio of 2-OHE1 and 16-alpha-OHE1 is linked with a lower risk of breast cancer. Working out seems to shift this ratio to favor the 2-OHE1 form.
In addition, being physically active helps with weight control. Post-menopausally, being overweight or obese is associated with a greater risk of developing breast cancer. Fat tissue releases inflammatory chemicals that may promote the growth of breast tumor cells. Staying lean is one thing you can do to lower your risk and reduce the risk of other chronic health problems as well. Also, deep, belly fat releases more inflammatory chemicals and is more strongly linked with breast cancer risk.
Finally, exercise, in moderation, has an anti-inflammatory effect. That’s important since a number of chronic health problems, including cancer, are correlated with ongoing, low-grade inflammation. Studies also show that exercise lowers markers of inflammation and reduces the risk of breast cancer recurrence in women who have had it. In fact, according to an analysis, exercise has the greatest impact of all lifestyle measures in lowering the risk of breast cancer recurrence and dying of breast cancer. That’s enough to make you put on your exercise shoes, isn’t it?
Being Fit Helps!
Studies in rodents show that simply being fit is linked with a lower risk of developing breast cancer. In rodents specifically bred to have a genetically higher or lower level of fitness showed that those with a lower natural fitness level were four times more likely to develop breast cancer relative to those with a higher fitness level. At least in rodents, those born with a high level of innate fitness seems to activate cellular signaling pathways that discourage the growth of breast tumor cells.
The Bottom Line
Exercise has so many health benefits! If you’re concerned about chronic, age-related health problems, exercise is your best defense. Combine a physically active lifestyle with a whole food diet and other healthy lifestyle habits, like limiting alcohol and not smoking, and you can reduce your risk of a variety of health problems and, potentially, slow the aging process itself.
When it comes to breast cancer prevention, know your risk factors. If you have a strong family history, you’ll need to be screened earlier than the average woman. Should you have a strong family history, consider getting genetic testing to make sure you don’t carry a gene mutation called BRCA-1 or BRCA-2 that places you at significantly higher risk.
The statistics are sobering, one out of eight, but breast cancer is a disease that can be modified through lifestyle, particularly physical activity. Take advantage of it!
Eurekalert.org. “What mediates the beneficial effects of exercise on breast cancer outcomes?”
New York Times Well. “Fitness May Lower Breast Cancer Risk”
Am J Epidemiol. 152:514-27, 2000.
Br J Cancer. 90(1):153-9, 2004.
Cancer Prev Res (Phila). 2013 Feb;6(2):109-18. doi: 10.1158/1940-6207.CAPR-12-0278. Epub 2012 Dec 4.
Cancer Epidemiol Biomarkers Prev. 2016 Jul;25(7):1009-17. doi: 10.1158/1055-9965.EPI-15-1061. Epub 2016 Apr 12.
Reuters. “Brief, Intense Exercise May Keep Breast Cancer at Bay”
Science Daily. “Exercise most important lifestyle change to help reduce risk of breast cancer recurrence”