Posted on: October 7, 2025
When data from runners and walkers were evaluated together, the risk for breast cancer mortality decreased by an average of 24% per MET hours per day of exercise, where 1 MET hour equals a little less than a mile of brisk walking or about two-thirds of a mile of running.
When the runners and walkers were analyzed separately, there was significantly lower mortality in the runners. The runners’ risk for breast cancer mortality decreased over 40% per MET hour per day. Runners who averaged more than 2.25 miles per day were at 95% lower risk for breast cancer mortality than those that did not meet current exercise recommendations. In contrast, the walkers’ risk for breast cancer mortality decreased a non-significant 5% per MET hour per day.
Thus, while walking did not appear to do much for breast cancer risk, running for 2/3 mile per day reduced the risk by 40%, with an optimal distance of 2.25 miles per day reducing the risk of breast cancer mortality by 95%.
Other studies also show that exercise can significantly reduce breast cancer mortality. In clinic, we encourage our patients to take up vigorous activity, such as running, biking or intense swimming.
References:
Schor, J. Impact of Running vs Walking on Breast Cancer Survival. Natural Medicine Journal. 2014:6(10) http://www.naturalmedicinejournal.com/journal/2014-10/impact-running-vs-walking-breast-cancer-survival
Williams PT. Significantly greater reduction in breast cancer mortality from post-diagnosis running than walking. Int J Cancer. 2014;135(5):1195-202. Epub 2014 Feb 28.