Estrogen causes breast cells to proliferate, and the more the cells proliferate, the more likely a mistake will be made during replication, which can lead to cancer. |
It's vitally important that women be asked about their lifetime history of exercise. |
The results indicate that the more exercise you do over your lifetime, the greater your reduction in breast cancer risk will be. In general, I think you need to do 3 to 4 hours of exercise per week to see a strong protective effect. |