Here’s another reason to get off the couch: Too much leisure-time sitting may increase the risk of breast and ovarian cancer in women.

A study that analyzed data from more than 77,000 women enrolled in an American Cancer Society prevention study found they were more likely to develop cancer if they spent more time sitting. Among the women in the study, more than 12,000 were diagnosed with some form of cancer.

Among the men in the study, researchers found no association between sedentary time and cancer risk. The reasons for the gender disparity when it comes to cancer risk are unclear. The findings were published recently in the journal Cancer Epidemiology.

Inactivity has been implicated in a host of health problems, but the link between sitting time and cancer has not been studied extensively.

The study also found that less-active women are also at increased risk for multiple myeloma, a type of blood cancer.

The American Cancer Society’s guidelines don’t spell out exactly how extra body fat, overeating and a lack of exercise heighten the risk of cancer. But the group says there is no question that they are linked to a greater cancer risk.

The American Cancer Society’s guidelines call for adults to get 150 minutes of moderate exercise or 75 minutes of vigorous exercise each week. Children and teenagers should get an hour of moderate or vigorous exercise every day, with vigorous activity at least three times a week.

Investigators say further research is needed to explain why inactivity seems to pose more of a cancer risk for women then men.

Researchers say you can cut your sitting time by walking for a few minutes every hour at work. Parking farther away from your destination also gives you more standing time.

Heeding this advice could help you be healthier and keep cancer at bay.