However, the effect is more pronounced in different groups of women.
Researchers analysed 62 studies looking at the impact of physical activity on breast cancer risk. They found the type of activity undertaken, at what time in life and the woman’s BMI all affected how protective the activity is against the disease.
Lean women who played sport or undertake other physically active things in their spare time, especially if they have been through the menopause, had the lowest risk of breast cancer, the authors said.
All types of activity reduced breast cancer risk but recreational activity reduced the risk more than physical activity undertaken as part of a job or looking after the house, the authors added.