The Role of Heat in Some Painful Conditions

Heat therapy, also called thermotherapy, has been used for many years to ease pain and improve movement.

Patients often ask whether they should apply heat to a painful or injured area. The answer depends on the type of problem, how long it has been present and how the area responds.

How does heat affect the body?

Heat can cause several local changes, including:

• Increased blood flow.

• Higher cell activity.

• Reduced muscle tension.

• Changes in how the nervous system processes pain.

• A temporary increase in movement tolerance.

  
  

Therapeutic heating is usually intended to feel comfortably warm, not hot. Excessive heat can burn the skin or damage tissue.

Movement remains the foundation

Heat may make movement more comfortable, but it is not a cure. Guided exercise remains an important part of rehabilitation because it can improve strength, movement and confidence.

If pain makes exercise difficult, heat may be useful as a short-term aid before or during gentle movement.

Superficial and deep heat

Superficial heat includes hot water bottles, heating pads, warm towels and warm water. It mainly affects the skin and tissues close to the surface.

Deep heating uses specialist equipment, such as therapeutic ultrasound or shortwave diathermy, to reach deeper tissues. These treatments are not suitable or necessary for every problem.

The type of heat matters because different methods warm different tissues at different rates.

How can heat help?

Heat may:

• Reduce pain for a short period.

• Help you relax.

• Make movement feel easier.

• Improve your tolerance of stretching or exercise.

  
  

Any increase in flexibility is usually temporary. Heat is most useful when it helps you move, exercise or sleep more comfortably.

When might heat be useful?

Superficial heat may help some people with:

• Low back pain.

• Osteoarthritis.

• Joint stiffness.

• Muscle tension.

• Longer-term pain problems.

  
  

Do not use heat over an area that is hot, swollen or acutely inflamed, such as a fresh injury. In these situations, advice on whether to ice an injury may be more relevant.

Heat should form part of a broader self-care plan, alongside suitable movement and rehabilitation.

Practical safety guidance

• Use a comfortably warm heat source, never one that feels hot enough to burn.

• Place a layer of clothing or fabric between your skin and the heat source if needed.

• Check your skin regularly.

• Stop if your pain worsens or your skin becomes very red.

• Do not fall asleep with a heating pad or hot water bottle.

• Ask a healthcare professional before using heat if you have poor circulation, altered sensation, diabetes, multiple sclerosis, rheumatoid arthritis, a spinal cord injury or a skin condition.

  
  

Final thoughts

Heat can be a useful, low-cost way to reduce pain and make movement easier for some people. Its benefits are usually short-term, so it works best when combined with appropriate exercise and lifestyle changes.

If persistent pain or stiffness is limiting your daily activities, a physiotherapy assessment in clinic or virtual support for pain and movement problems can help identify the most suitable rehabilitation plan.

If you want more detail about how heat works inside the body and when it’s most effective, you can read the long‑form explanation.

About the Author

Dan Watson is a Chartered Physiotherapist based in Colchester, Essex. He specialises in clinical physiotherapy, sports injury assessment and return‑to‑performance rehabilitation.

With over 15 years experience, Dan has supported everyday patients and professional athletes across football, rugby and the Royal Ballet. His approach blends clear assessment, practical education and progressive exercise tailored to each person’s goals.

He regular provides face‑to‑face physiotherapy in Colchester and online support for patients suffering with both acute and long term pain across the UK.