Here's a good reason to go for a short walk or run today: While prior research has already found that regular exercise can reduce breast cancer risk by about 25 percent, a new study suggests that those numbers are even greater than previously thought.

Even small amounts of regular exercise, such as regularly going on short runs or walks, potentially lowered a woman's risk of dying from breast cancer by more than 40 percent, findings showed.

Researchers from Lawrence Berkeley National Laboratory in Berkeley, California, looked at breast cancer mortality in nearly 80,000 women during the 11 years following their baseline survey.

None of the women reported a history of breast cancer before the study's launch, and each subject kept diaries on the distances that she walked or ran every week.

Findings showed that women didn't have to be serious athletes to reap the benefits, and that even a dose of seven miles per week of brisk walking or 4.75 miles per week of running were enough.

The evidence was published online this week in the journal Plos One.

Looking for other ways to reduce your risks of breast cancer? US breast cancer expert Erica Mayer of the Dana-Farber Cancer Institute, a principal teaching affiliate of the Harvard Medical School, suggests getting a mammogram starting at 40, keeping your weight in check, eating a mostly plant-based diet, and limiting your alcohol intake.