Running is the king of cardio. Running even five to 10 minutes a day, at slow speeds (how does a nice 12-minute mile sound to you?) is associated with a drastically reduced risk of dying from cardiovascular disease, according to a landmark study in the Journal of the American College of Cardiology. Compared with never-runners, regular runners have half the chance of dying from heart disease. Every time you run, you decrease your resting heart rate, so your heart doesn’t need to work as hard, says exercise physiologist Greg Justice, founder of AYC Health & Fitness in Kansas City.