Long-term rigorous exercise plays a protective role against invasive and in situ breast cancer, according to research.
Previous studies have linked exercise with a reduction in breast cancer, but few studies have examined the risk separately for the two types of cancers, said the authors.
The US study found that invasive breast cancer was reduced among women taking strenuous activities for more than five hours per week annually, when compared to the least active women. Similar results were seen for in situ cancer.
Researchers analysed data collected from 110,599 women with no prior history of breast cancer and aged between 22 and 79 years at the start of the study.During the six and a half year study2,649 women were diagnosed with breast cancer.
Archives of Internal Medicine (2007) 167: www.archinternmed.com