Researchers in France discovered that women who exercise for an hour a day can reduce their risk of breast cancer, regardless of their age or weight.
The scientists presented their findings to the European Breast Cancer Conference, according to Science Daily. They said that women with a higher level of physical activity reduced their risk of breast cancer by 12 percent.
The researchers looked at the results of 37 studies, involving over four million women and found that women, no matter their weight or age, who exercise for an hour a day all received a similar benefit, including women with more aggressive cancers. They said weight control is not the only reason for the benefits since the results are not represented by body mass index (BMI), Daily Mail reported.
"These are the studies looking at the relationship between physical exercise and breast cancer risk that have been published to date, so we are confident that the results of our analysis are robust," said Prof. Mathieu Boniol, research director at the International Prevention Research Institute of Lyon, France.
The benefits of exercise were cancelled out in women taking hormone replacement therapy (HRT), Science Daily reported. However, growing understanding of side effects of HRT means its use is decreasing, which means the benefits of activity will likely increase in the future.
"Whether or not this will be the case is an interesting question and deserves to be followed up at a later date," Boniol said.
Boniol added that while the study focused on intense exercise, women who weren't as active saw benefits as well. He said that more activity is better, but moderate activity could also produce results, NPR reported.
Dr. Hilary Dobson, chairwoman of the conference's national organizing committee, commented on the significance of the study in motivating women to be active, Science Daily reported.
"These findings are important for all women, irrespective of their age and weight," Dobson said. "Whilst the mechanism for the potentially protective effect of physical activity remains unclear, the analysis, which is presented here, provides women with a real impetus to increase their physical activity by even modest increments. This review seems to be telling us that the resultant improvements in breast health can now be added to the other established health benefits of physical activity."
