In a large, long-term study, researchers rated the participants' heart health using the seven health indicators from the American Heart Association Life's Simple 7. Among participants with optimum health, the risk of blood clots was 44 percent lower than those with inadequate health. Those with average health had a 38 percent lower risk. Maintaining ideal levels of physical activity and body mass index were the most significant lifestyle changes related to lower risk of blood clots. Here are the "Simple 7" for reducing your risk.