YOUNG women who exercise 13 hours a week could lower their risk of breast cancer by up to 25 per cent, research has revealed.
Women will no longer have an excuse not to hit the gym with the latest research showing the earlier a girl becomes active, the lower the risk of breast cancer before menopause.
The analysis of the effects of exercise on premenopausal breast cancer, involving 65,000 women found that those who were physically active from the age of 12 had a 23 per cent lower risk of breast cancer.
In particular, high levels of physical activity between 12 and 22 contributed most to the lower risk.
Dr Helen Zorbas, CEO of the National Breast Cancer and Ovarian Cancer Centre, said the benefits of exercise were well known.
“It’s important and an empowering outcome for young women,” she said.
“It focused on detailed activity but the more you do, the better the effect.
“Thirteen hours a week for the most active woman but there were benefits for all levels of activity.”
For the greatest reduction, 13 hours of walking a week is recommended or 3.25 hours of running.
The study, by researchers at Washington University School of Medicine in St. Louis and Harvard University in Boston, also found recreational activity reduced the risk.
Household chores can have equal benefits but vigorous exercise is needed for optimum results.
“A number of studies show regular physical activity totalling four or more hours per week reduces the risk for breast cancer in post-menopausal women,” Dr Zorbas said.
“There hasn’t been a study before into pre-menopausal women.
“There are a number of theories to explain this reduction in risk, including the effect of exercise on reducing a woman’s exposure to estrogen, which is known to play a role in the development of breast cancer.”
A fourth of breast cancers are found in women before menopause.
Numerous studies have shown that the more estrogen a woman is exposed to, the greater her risk.
But women who begin menstruating later or enter menopause early have a lower risk of breast cancer.
For those like Denise Tobin, who like to exercise, the findings are welcome news.
The 24-year-old from Bondi has been into sports since she was young.
“I’ve always done about two or three sports,” she said.
“I go to the gym three times a week and go for a walk every other day.
“I do it because I know it’s good for me and I like to keep fit.”
Researchers surveyed 65,000 nurses in America on their physical activity between the ages of 12 and 35.
They found the rate of breast cancer dropped significantly in women who said they started exercising while at school and remained active throughout their lives.




The actual answer is that the media causes cancer. And cures it!