Heat can be applied in many ways; using a heat pack, using warm water, or using
warm wax. The purpose of applying heat is usually to decrease pain. It can help
muscles to relax and it can affect your nerves in order to decrease your pain.
Heat can also help to bring blood and nutrients to the area and therefore increase
healing.
Heat or heat pads should never be left on for longer than 20 minutes or it
can cause other problems like skin damage or swelling. Therefore, most physical
therapists would advise you not to use an electrical heating pad to sleep with.