What he says. A coworker races dirt bikes in the 50 year old age classes. He trains hard and plays hard. Had the same thing happen.I walk two to five miles 5x per week all year and do a 2+ hr workout at the gym at least 2x per week during the colder months. The excecise you need to prevent this condition is 5 minutes of solid activity to get pooled blood moving. Even if you are in fantastic shape, DVT can happen.