New research showed that taking more regular exercise and sitting less helps to reduce breast cancer risk.  The study published in The British Journal of Sports Medicine involved >130,000 women. It compared 70,000 which had a breast cancer (BC) that had spread  and 7000 with  a BC that had not spread as well as >50,000 women who did not have BC.

They found that those women who were more physically active had a >40% lower risk of  BC, regardless of their tumour type. Both pre-and post-menopausal women had a lower risk of  BC if they were more physically active and less sedentary. Those who exercised vigorously on 3 or more days a week had a 38% lower risk of BC compared with those who did no vigorous activity.

Sitting and triple negative breast cancerThere are numerous underlying mechanism of why exercise has anticancer properties ranging from reducing expression of cancer promoting genes and improving gut health and these have previously been summarised in a paper also published in the British Journal of Sports Medicine.

Prolonged sitting time — being sedentary — is an independent risk factor for various different diseases including heart disease, Type 2 diabetes, and dementia.  For the first time, this study showed that those who spent a longer time sitting were associated with an increased risk of a more aggressive type of breast cancer — triple negative breast cancer. Interestingly, triple negative breast cancer is more likely to be associated with inherited mutations in the BCRA gene. Other studies have suggested that exercise can help restore function in mutated BRCA genes.

Take home message

This study further supports that we can have some control over our destiny with sensible and  enjoyable lifestyle choices. In particular, to reduce the risk of breast cancer, make time for moderate or vigorous intensity exercise during the week and reduce our time spent sitting – especially if you have a history of BC in the family.

If you have desk job try to stand and shake your legs every 20 mins and try to walk at lunch time, before and after work.


Dixon-Suen SC, Lewis SJ, Martin RM, et al. Physical activity, sedentary time and breast cancer risk: a Mendelian randomisation study. British Journal of Sports Medicine Published Online First: 06 September 2022. doi: 10.1136/bjsports-2021 – 105132 3. SNP. 2014

Thomas RJ, Kenfield SA, JimenezExercise-induced biochemical changes and their potential influence on cancer: a scientific review.