One of the oldest remedies in existence has been the application of heat or cold to a recently injured area. There is plenty of evidence that shows that a change in temperature can affect various systems of the body. But knowing which one is correct for the type of injury at hand isn’t as commonly know a fact. As your body reacts to heat and cold differently, different types of injuries, and different stages of injury, would require one or the other. Immediately following an injury swelling occurs in the affected portion of the body. This is caused by ruptures in the capillaries in the surrounding area causing blood to collect. Applying cold is the correct remedy for this situation. The colder temperature causes the capillaries to become more narrow thus allowing less blood to reach the area reducing the swelling. In contrast, heat has the opposite effect which can make the swelling worse. The more blood is prevented to leak into the area, the worse the swelling and the longer the recovery process. In the time following the injury, heat should now be applied. Once the capillaries have had time to clot, there will be no more blood rushing into the injured area. Heat can help to relax the muscles and tissues and ease pain. If ice is applied at this point, it can make muscles stiff and painful.