Walking for two hours daily can significantly reduce breast cancer risk in postmenopausal women, according to a new study.
The MARIE study involving 3,464 breast cancer patients and 6,657 healthy women, between the ages of 50 and 74 years, showed that risk of developing breast cancer after menopause was lower by about a third in the women who were physically most active.
Professor Dr. Jenny Chang-Claude and colleagues from the German Cancer Research Centre and the University Hospitals of Hamburg-Eppendorf questioned the participants about their physical activity during two periods in life: from 30 to 49 years of age and after 50.
The women in the physically most active group walked for two hours every day and cycled for one hour, while the most inactive study participants walked for only about 30 minutes every day.
A closer look at the types of breast cancer revealed that physically active women were less frequently affected, particularly, by tumours that form receptors for the two female sexual hormones, namely oestrogen and progesterone.
The researchers believe that physical exercise reduces the risk of cancer through hormonal mechanisms instead merely by a reduction of body fat or other changes in physical constitution.
"It doesn't always have to be sports," said Associate Professor Dr. Karen Steindorf of DKFZ, who has headed this analysis.
"In our calculations we have also taken account of activities such as gardening, cycling or walking to the shops.
"Our advice to all women is therefore to stay or become physically active also in the second half of your life. You will not only reduce your risk of breast cancer, but it has been proven that your bones, heart and brain also benefit from it," Steindorf added.