Physical fitness has been shown to delay age-related arterial stiffness, a risk factor for cardiovascular disease. New study: Participants sat on the floor, legs straight, then bent forward at the waist to see how far they could reach toward or past their toes. Among middle-aged and older adults, the least flexible people generally had the stiffest arteries, as measured by a test called pulse wave velocity. Researchers theorize that stretching exercises may prompt physiological reactions that slow age-related arterial stiffening. Best: Incorporate flexibility exercises, such as stretching, yoga and Pilates, into your regular workouts.