1. Use heat for stiff or tight muscles, including knots.
2. Use heat for stiff joints, especially before stretching them. This will help to maximize the range of motion achieved with stretching.
3. Use heat for short-term pain relief of a body part. Use a heating pad for 10-15 minutes. Be sure not to fall asleep on a heating pad because burns can result. Also, be cautious not to have the intensity of the heating pad too high. If the lowest setting on your heating pad feels too hot, use towels to layer between your skin and the heat.
4. Use heat as an adjunct to relaxation techniques.
5. Use heat as a form of pain control for back pain and/or neck pain. However, if you rely on heat regularly or daily for pain relief, you may have an injury or problem that needs to be addressed medically.
6. Use heat to treat stiffness in the hands (such as from rheumatoid arthritis). Dip your hands in a sink or bucket of warm water for several minutes.
7. Do not use heat on a new injury, area of inflammation or swollen area.
8. Do not use heat over the area of a blood clot, hemorrhage or malignancy.
9. Do not use ice or heat if you have decreased sensation in that part of the body.
Cameron, Michelle H. Physical Agents in Rehabilitation, From Research to Practice, 2nd ed. 2003: Saunders. Pages 158-180. (Chapter 6: Thermal Agents: Cold and Hot).