It’s no secret that body fat increases postmenopausal breast cancer risk. Regular exercise is an integral part of breast cancer prevention and, further, exercise should play a key role in breast cancer recovery as well (we posted a blog on the subject last summer). But how much exercise is optimal for reducing breast cancer risk? According to a recent study, more seems to be better.
A clinical trial conducted in Alberta, Canada between 2010 and 2013 studied how different levels of exercise affected the body fat levels of 384 previously inactive postmenopausal women (aged 50 to 74 years) in both normal and obese body fat ranges. The participants were randomly assigned workout regimens of either 30 or 60 minutes per day for five days each week (with no dietary changes) and continued the regimens for 12 months. Body fat measurements taken before and after the trial showed that decreases in body fat were significantly higher in those women who participated in a higher volume, more intense exercise regimen (300 vs. 150 minutes per week).
Overall, the women exercising 300 minutes weekly lost 1% more body fat than those in the 150 minute group. An important finding, however, was that those exercising at the higher level did not lose significantly more weight. Many cancer studies focus on how weight affects cancer risk, but this study focused specifically on body fat levels.
Christine Friedenreich, PhD led the study along with her colleagues at Alberta Health Services in order to differentiate between how body fat, not just weight, could lower cancer risk. She said that general guidelines for exercise concentrate on lowering blood pressure and other heart disease-related measurements. But for cancer prevention, Friedenreich says, “We may need to exercise at higher volumes. So yes, doing 150 minutes of activity a week is good, but if you can do more, then from a cancer prevention perspective, 300 minutes is better.”
Since fatty tissue is the main source of hormones that can drive postmenopausal breast cancer, the study results are significant. Fat also plays a role in the body’s immune and inflammatory responses, both of which are involved in cancer. So when it comes to exercise and breast cancer prevention, upping your game could really improve your odds!