Using Heat for Pain Treatment

Treat Chronic Muscle and Joint Pain with Heat

Senior man suffering from knee pain
Gurpal Singh Datta/Getty Images

When heat is applied to the skin, it causes more blood to flow into the area where it is applied. Heat affects the skin as well as the underlying tissues below the skin. How deeply these effects travel depends on what type of heat is used for treatment. For instance, a heating pad may only target the "shallow" tissues, which are directly below the skin, while a therapeutic ultrasound can penetrate into the deeper muscles.

How Heat Helps Pain

When blood flow increases to a particular area of the body, it brings along oxygen and nutrients that can help to speed up the process of healing. Heat helps to relax muscles, which can work to decrease some types of pain sensations. The sensation of heat on the skin also provides something called an analgesic effect: it alters the perception of pain so you don't hurt as much. The presence of heat on the skin can also be soothing. 

How to Use Heat for Pain

Using heat at home can be as simple as plugging in a heating pad, or filling up a water bottle with warm water. In fact, many heating products available on the market don't even require a plug or water: single-use air-activated heating pads can be worn all day, and then thrown away. Some therapy clinics use paraffin wax dips, which, while somewhat messy, can be purchased for use at home. These are usually reserved for hands and feet (it's physically hard to "dip" your lower back).

You can also target many different areas at once with heat therapy by soaking in a warm bath, or stepping into a hot tub.

When to Use Heat for Pain 

Heat can be used to relieve pain caused by chronic conditions of the muscles and joints. Such chronic conditions include:

  • Muscle spasms
  • Muscle stiffness

Because heat has a pain-relieving effect when applied to the skin, it can also be used for other chronic pain conditions as well. In fact, many people in our therapy clinic request heat for nerve pain conditions as well as back pain caused by disk problems. There is little research evidence to suggest that using heat improves these conditions; however, many of patients still find the use of heat comforting.

When NOT to Use Heat for Pain

While the use of heat can be beneficial for pain treatment, there are also situations when heat should not be used for pain treatment. Heat is best for injuries or conditions that are not in the acute phase. In other words, don't use heat on a fresh injury: you could increase swelling, which in some cases could increase your overall level of discomfort. In these cases, ice is a better choice. Also, you shouldn't apply heat over irritated skin or open wounds (including incisions that are still healing). Finally, people with cancer should not use heat to treat pain, as there is a chance of increased tumor growth.

Related article: Should I Use Heat or Ice for My Pain?

Sources:

Belanger, Alain-Yvan. "Evidence-Based Guide to Therapeutic Physical Agents" Philadelphia: Lippincott Williams & Wilkins 2003

Gould, Harry J. "Understanding Pain: What it Is, Why it Happens and How It’s Managed" New York: AAN Press 2007

McCarberg, Bill and O’Connor, Annie. American Pain Society Bulletin. 14:6, 2004.

O’Connor Annie and McCarberg Bill.  American Pain Society Bulletin. 15:1, 2005.

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