The research was conducted by experts from the University of California, San Francisco Medical Center, Georgetown University, and University of Washington School of Medicine who gathered and examined data from over 85,000 postmenopausal women in the U.S.
All subjects were aged 50 and older and took part in the Women's Health Initiative study. They were given an exam to measure their weight and height so doctors could determine their BMI (body mass index).
Annual surveys were given to the participants so that the experts could keep track of what they were eating. The scientists wanted to take into account factors known to lower the risk of kidney stones, such as drinking a lot of fluids and consuming less salt or meat.
Volunteers reported how much physical activity they generally got, which translated into "METs" - a measure of how much effort is put into an activity. Two and a half hours of walking, for example, or one hour of jogging, translates to 10 METs each week.
Three percent of the women had developed a kidney stone after about 8 years. The volunteers who got up to 5 METs each week had a 16% reduced likelihood for kidney stones, compared to those who did not get any exercise.
With 5 to 10 METs each week, the probability was reduced by 22%, and with 10 METs or more, the risk was lowered by 31%.
The important element in lowering the risk of kidney stones is not the intensity of exercise, but the amount, the authors explained.
Cutting the amount of high-calorie foods consumed can also help lower postmenopausal women's risk of kidney stones by over 40%, the researchers found.
According to HealthDay News, AUA spokesman Dr. Kevin McVary said in a news release:
"Kidney stones are a very common health condition, and as with most health conditions, prevention is key. While we know diet is one of several factors that can promote or inhibit kidney stone development, this study shows lifestyle changes such as exercise can also help prevent stones from forming in postmenopausal women. Further research is needed to understand if this observation is accurate for other demographics."
The results of the study, presented at the annual meeting of the American Urological Association, should be thought of as preliminary until they are are published in a peer-reviewed journal.
Each year, over 3 million people in the U.S. seek help from a health care provider for a kidney stone and more than half a million visit an emergency department.
A previous study showed that smoking and drinking are responsible for the dramatic rise in women developing kidney stones.
Written by Sarah Glynn