Researchers looked at 70,000 women enrolled in the Nurses' Health Study, over an 18-year period. They found the risk of developing a pulmonary embolism was more than double in the women who were sedentary, compared to those who were active. And weight had nothing to do with the risk.
Experts say the best way to avoid clots is to get at least a couple of hours of movement a day. That's because clots are partly caused by a lack of blood flow.
The study is in the British Medical Journal.