Heat therapy is one of the most ancient and common treatments used for relieving lower back pain. When someone comes to see me with back pain I always ask them if they have tried anything yet for pain relief. The most common answer is back pain medication, but the second most common answer is heat.
One of the advantages of this treatment is that it is offers natural pain relief and many people feel comfortable using it. A quick look at www.patientslikeme.com (see ref below) shows that 450 patients are using it, most of them for pain and that they use it between 20-30 minutes on average. Many them find it helpful but you do have to watch out for side effects and robustly take great care not to burn. I would advise that you do not lean or rest against the pad/heat and that you keep a close eye on how your skin is looking. Don't use it at all if your sensation is altered as you may burn. Use common sense in a word and if you are not sure talk to your doctor.
Heat comes in all sorts of shapes and sizes ranging from the humble hot water bottle, right through to heated pads (these * Thermacare Heat Pads are the ones used in the research mentioned below)and infra red lamps.
Heat therapy increases the blood supply to an area.
It does this by causing the blood vessels to widen or dilate. You can see this by the pinkness of an area exposed to heat. This may have several effects.
Heat therapy activates the pain gate.
As with TENS, acupuncture, acupressure and massage, stimulation of a sore area effectively reduces the volume of the pain signals being ‘heard’ by the brain. This is the same mechanism that is in play when we instinctively rub something when we have hurt it i.e. knocking an elbow.
Heat therapy causes the release of endorphins
Endorphins are the bodies own natural pain killers. As we know from stories of people in pain, the body can modulate pain by releasing opiates which diminish the sensation of pain (the brain can also increase pain but that’s another story – if you are interested read more here)
There is not much good evidence to draw on but the last review of heat therapy (1) found some evidence that it reduces back pain in patients that have had pain for less than three months (acute pain). However, the effect only lasts for a short time. There is nothing to show it works if you have had pain for longer than three months (chronic pain).
Interestingly this review also found that combining heat with exercise is better again.
RESEARCH UPDATE 2012
This systematic review was updated in 2010 and the authors found no further evidence either way so the original conclusions are still valid
A newer study (2) has looked at heat compared to placebo tablets in a small sample and shows the heat is better at pain relief. This is a bit of a weak study because it is not controlled but it still adds to the research a little. Again this is just acute or less than 6-12 week old pain.
If you use heat make sure you do not burn. Patients with poor skin sensation or temperature awareness should not use it. Remove the heat if it becomes uncomfortable, do not press down on heat i.e. lie on a heat pad and do not fall asleep while using it. Discuss the use of heat with your health care professional.
1. French, S. D., Cameron, M., Walker, B. F., Reggars, J. W., & Esterman, A. J. 2006, "A cochrane review of superficial heat or cold for low back pain", Spine, vol. 31, no. 9, pp. 998-1006.
2. Petrofsky, Jerrold, Berk, Lee, Bains, Gurinder, Hau, Benny, Doyle, Geraldine, Chen, Shijie, et al; The Efficacy of ThermaCare Heat Wraps on Relieving Lower Back Pain and Reducing Muscle Stiffness. Arthritis Rheum. 2011;63(Suppl 10):1069..
Heating Pad-Hot Packs Report for Patients Like You: PatientsLikeMe [Internet]. [cited 2012 May 11]. Available from: http://www.patientslikeme.com/treatments/show/3243-heating-padhot-packs-side-effects-and-efficacy