Breast Cancer and Exercise
William H. Neumeier, PhD
The month of October brings many things to mind. October is known for cooler air, costumes, candy, and smiles. Leaves shed the green of spring and summer and adorn reds, oranges and yellows instead. We accentuate the colors of fall with scarves, long sleeve shirts and boots that blend with nature’s fresh wardrobe.
There is another prominent color in October that solidly stands on its own; the color pink. Pink during the month of October represents breast cancer awareness. Sports teams, fitness events, organizations, corporations, and many other places adorn pink accents over their every day emblems.
At NCHPAD, we are able to focus on exercise related benefits year round. For the month of October I would like to add a pink emblem to that focus and bring attention to the relationship between breast cancer and exercise.
Epidemiological research (i.e., research examined at a large, population level) has demonstrated that increased exercise is associated with reduced risk of breast cancer development and breast cancer recurrence. Though the relationship between exercise and breast cancer is becoming better known, scientists still do not understand why increased exercise may reduce breast cancer rates. In addition, only an association has been established between exercise and breast cancer; we have yet to establish cause and effect. Perhaps people that exercise also participate in other health behaviors that could reduce the risk of breast cancer, or perhaps there is another reason for the relationship. Again, we are left with the notion that exercise is beneficial, but we are not really sure how it is beneficial, especially in relation to breast cancer.
A new study may have shed some light regarding how exercise impacts cancer cells. In the study, researchers genetically selected and developed rats with high or low fitness levels. Then they exposed the rats to a chemical that is known to be a potent trigger for breast cancer. Rats with low fitness levels were four times as likely to develop breast cancer compared to the rats with high fitness levels. The researchers also discovered differences in a protein pathway, known as mTOR, between the rats of high or low fitness. The mTOR pathway is related to cell division, and past studies have observed higher mTOR activity in women with breast cancer. The higher fitness rats had reduced mTOR activation compared to the low fitness rats.
This is very exciting news, but a word of caution is necessary. This study was conducted with rats, and rats are very different from humans. Only a few animal studies may directly translate to results with humans. Despite this difference, the study provides an interesting insight to how exercise may prevent cancer. So as you watch the colors change from summer to fall and you notice pops of pink throughout the month, don’t just think about the cooler weather and breast cancer. Instead think, “It’s a nice day to get some exercise outdoors.”