Arteries are blood vessels which transport blood in and out of the heart and to all parts of the body. Each one is shaped like a tube and, as people age, they are prone to stiffening and weakening. Research suggests that exercising four to five times a week is necessary to stop the main arteries to the heart from stiffening up. With this amount of exercise, it’s possible for people to slow and possibly reverse the aging of the heart and blood vessels.