Heat Therapy for Pain Relief – Is it Effective? (Clinical Trials & Credible Sources)

According to this American Academy of Pain Medicine (AAPM) study, every year 76.5 million Americans experience pain that lasts at least 24 hours, not including the people suffering from chronic (long-lasting) pain. The healthcare cost related to pain in 2010 was between $560 billion to $635 billion.

The go-to remedies for pain are the usual suspects – the anti-inflammatory drugs (NSAIDs). The NSAIDs are great if taken on rare occasions, but for commonly reoccuring, or long-lasting pain, taking a more natural approach may be wiser. We decided to dedicate this post to one of these natural approaches to pain relief – heat therapy. Outline:

  • Effects of Applying a Heating Pad
  • What Do Doctors Say Regarding Heat Therapy?
  • What Do Clinical Trials Prove on the Matter?
  • When Should We Avoid Heat?


harvard medical school quote

Because multiple studies connect the regular use of anti-inflammatory drugs with some severe side effects. For example, this New England Journal of Medicine study shows that frequent use (once a day) of anti-inflammatory drugs significantly increase one’s chances of renal (or kidney) disease. In addition, this huge Thai study concluded that people who suffer from high blood pressure have 32% higher chance of experiencing a chronic kidney disease if they have taken NSAIDs daily, for at least 90 days. Furthermore, this Harvard Medical School article states the regular use of anti-inflammatory drugs can also increase the chances of having a heart attack.


Increases Blood Circulation

When you apply heat to a certain part of your body, the blood vessels (veins and arteries) in the heated area of your body widen. When your blood vessels widen, they create less resistance to your blood. Therefore, more blood flows in and out of the heated area. This whole process is called Vasodilation. Vasodilation is a friend because it helps decrease your blood pressure and heart rate. In case you would like to read up on Vasodilation, check out this article by an Indian medical school.

Relaxes Muscles

Heat causes your smooth muscle cells to relax. This is, actually, one of the reasons why Vasodilation is able to occur. Overall, relaxing your muscles is an obvious and widely desired benefit we needn’t spend much time on in this post.


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Most physical therapists apply or recommend the use of superficial heat (a.k.a. heating pad) in the healing process of many different injuries.

Furthermore, a large number of different medical schools and organizations recommend heat therapy (and/or ice) for many different conditions. The University of Minnesota Medical School recommends heat therapy for (and/or cold therapy) for general physical pain relief. Harvard Medical School, Arthritis.org and the University of Washington recommend the use of both moist and dry heating for treating pain from different forms of arthritis. Harvard Medical School lists heat as a remedy for foot pain (like pain from wearing uncomfortable high heels or work shoes for long periods time) and UK HealthCare Sports Medicine Patient Education recommends heat as a treatment for Plantar Fasciitis pain in your heel.

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In addition, Physiopedia and Harvard Medical School both recommend heat for decreasing joint stiffness, which is especially beneficial to those suffering from arthritis.

Links to sources, in order of appearance:

1, 3, 4, 5, 6, 7, 8, 9


scientists conducting a research

Let’s begin by stating that the conclusions of the clinical trials on the subject are not completely satisfying. Most studies concluded that heat made a statistically significant difference in pain relief, however, all other trials end by stating that further research is required and by admitting to poor trial quality. Poor trial quality may be caused by a ton of different factors, such as a small sample size, lack of patients’ oversight, poor randomization, not placebo-controlled, and others. Nevertheless, here are some studies that recognize the effectiveness of heat therapy:

  • This Academia.edu study suggests that heating pad application does indeed relieve neck pain and improves the function of the Somatosensory Cortex, which is the part of your brain that processes sensations. The study consisted of 50 people.
  • In this trial randomized controlled trial, 344 participants were evaluated to determine whether a heating wrap or a 1000mg of acetaminophen contributed to greater menstrual pain relief. The participants who received treatment with the heating wrap reported greater pain relief and a greater decrease in tightness and fatigue than the participants who were given acetaminophen. To learn more about heat therapy for menstrual pain, check out our post on menstrual cramp remedies.
  • In this research paper published by Intech, doctors concluded that heat reduced pain and improved physical function for those suffering from Osteoarthritis (and other kinds of arthritis)
  • In a study of two trials, 258 people were treated with heat therapy for their mild-to-severe lower back pain. The results showed that heat wrap therapy significantly reduced pain after 5 days, as reported here.
  • Microwavable heating pads are also found to be very helpful (as showed in this study) for an enlarged prostate gland. They effectively relieve urinary symptoms and urinary flow problems.


Please, give your doctor a quick call before using heat therapy. There are occasions where it can do more harm than good. For example, heat is NOT RECOMMENDED within the first 3 days of most fresh injuries. In the early stages of an injury, heat may bring more pain and prolong the healing process. In general, heat therapy isn’t recommended for swollen or bruised areas. Heating pads can also be dangerous for people with skin sensitivity irregularities. For example, many people suffering from diabetes may get skin burns, as they are unable to sense that their heating pad is getting too hot.

If you do have diabetes, you should have someone supervise you while applying heat. Also, look for heating pads that do not exceed temperatures of 110 degrees Fahrenheit. For certain conditions, like deep vein thrombosis (and others), heating pads may do more harm than good. Heating pads, if not used properly, can also present a fire hazard. Treat them with respect. Infrared heating pads should not be used by people with metal implants and/or any form of implants.


The existing trials dedicated to determining the efficacy of heat therapy for pain relief does not provide high-quality evidence to be a proof on its own. However, the combination of the evidence collected from those trials and the all the other credible sources recommending heat, there’s a strong reason to believe that it does help.

Thermotherapy is an extremely popular remedy, prescribed by physical therapists, trainers, and even MDs. Tons of reputable medical universities refer to heating as a remedy for many different conditions and injuries.

Studies overwhelmingly show that the level of heat you need is most likely between 104 and 110 degrees Fahrenheit. These temperatures may not feel as hot as you’d prefer but they are all you need to increase blood flow in the problematic area. Anything over 110 degrees may result in burns so call your doctor and ask for their opinion.

If you wish to give heat therapy but you’re not willing/able to pay for a heating pad, head over to YouTube and search “homemade heating pad”. No one in our team has made one, but it seems to only take three minutes.

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