A baby aspirin a day or you can wear a jobe stocking, it's a compression sock that helps the blood flow in your leg(s).....I've had a few battles with blood clots the past 10 years as well as torn ACL so sitting long period of time hurts my knee but the sock does help and I take a baby aspirin per day just because........but like joeyc said sitting LNG period of time, work, driving or long flights can make you more prone to blood clots and you don't want tht, it's nasty and dangerous, especially the meds....really mess with what you can and can't do as well as diet and certain foods you can't eat....