Women who walk at a brisk pace on a regular basis are less prone to developing breast cancer after menopause, as opposed to their inactive counterparts with sedentary lifestyles, a study has said. Those who got little exercise but boosted their activity after menopause were 10 per cent less likely to develop the disease.

Investigating reports about nearly 100,000 postmenopausal women, researchers found that women who scheduled at least an hour of brisk walking per day (or an equivalent amount of activity) were 15 percent less likely to get breast cancer than women who walked less than one hour per week.

Researchers note that over five in 100 women got breast cancer over 20 years in the study published in the Archives of Internal Medicine.

There are many risk factors for breast cancer that women have no control over, such as family history or the age at which they begin menstruating, study author Dr. A. Heather Eliassen told Reuters Health. However, they can do something about their physical activity regime.

While research suggests that very active women often fight breast cancer easily, there’s very little known about those with moderate exercise routines. Researchers worry that they can’t analyze the benefits of exercising comparing any previous studies, as many studies are designed differently, and ask different questions about how much activity women are getting.

In the study, Eliassen and her team at Harvard reviewed data collected from 95,396 women who were followed for 20 years. At regular intervals, women reported how active they were, and the types of exercise they chose to do.

The researchers found that regular exercise was associated with a lower risk of breast cancer even after removing the potential influence of drinking and weight.Researchers took into consideration activities such as swimming, hiking, or jogging as well, and found that they were associated with the lowest risk. However brisk walking appeared to be the most protective against breast cancer. The good news is that women didn't need to engage in vigorous workouts to see a benefit -- it's enough to simply walk at a brisk pace, roughly three to four miles per hour.

The authors couldn‘t prove whether walking caused less breast cancer, as there may be other factors common to women who walk more that made them less likely to develop it. Still, the results are suggestive, they note.

Exercise reduces estrogen in the blood, which can affect breast cancer risk. But in this study, it also reduced the risk of breast cancers that aren't influenced by estrogen, suggesting there are other explanations. They also observed that physical activity also has an effect on chronic inflammation, and insulin sensitivity.