A warm up is the act of preparing for an athletic event or workout by exercising or practicing for a short time beforehand. Warming up helps reduce your risk of injury and the aches and pains that come with exercise. The physiological reason to warm up is to assist your circulatory system in pumping oxygen-rich blood to your working muscles. The idea is to increase circulation throughout the body in a gradual manner. A proper warm up safely prepares the body for the increased demands of exercise. Cold muscles do not absorb shock or impact as well, and are more susceptible to injury.