A new study is challenging the idea that you can be fat and fit.

The study tracked nearly 39,000 women for more than a decade and found that while being active can lower the risks of heart disease in heavy women, it doesn't eliminate them.

When compared with active, normal-weight women, the risk of developing heart disease was more than 50 percent higher in active but overweight women. But for inactive overweight women it was nearly 90 percent higher.

The study's lead author calls it "reassuring to see that physical activity does make an impact." But Dr. Amy Weinstein added, if a person is overweight, physical activity alone isn't enough.

Previous research has gone back and forth on whether weight or exercise has more influence on the risk of heart disease.

The study is published in the Archives of Internal Medicine.