Deep Heat Treatment

What is deep heat treatment?

Deep heat treatment is a therapy that sends heat below the skin surface into tissues and muscles. Deep heat treatments are used by health care providers such as physical therapists, chiropractors, and dentists.

When is it used?

Deep heat is used to:

  • reduce pain such as low back pain
  • relieve muscle spasm
  • loosen soft-tissue contractures (muscle shortening that affects your joints)
  • treat chronic arthritis, bursitis, and fractures
  • treat inflammation and promote healing.

It may be used after cold treatments when inflammation and swelling are gone.


Deep heat treatments should not be used if you have:

  • circulation problems
  • cancer that has recently been treated with radiation therapy
  • heat intolerance
  • lack of sensation in the area being treated
  • metal implants such as pacemakers or IUDs
  • heart, lung, or kidney diseases.

Deep heat treatments should not be used on areas above the eye or around the heart, or if you are pregnant.

How does it work?

The 3 main types of deep heat treatment include:

  • high-frequency currents (shortwave diathermy)
  • electromagnetic radiation (microwaves)
  • ultrasound (high-frequency sound).

Deep heat speeds up healing by increasing blood flow to the injury. Electromagnetic heat, such as shortwaves and microwaves, sends heat up to 2 inches into the tissue and muscles. It works best for injuries in joints, muscles, and tendons. Heat therapy may help reduce pain.


Before you receive heat treatment, you must remove all metal objects, including jewelry, glasses, and hearing aids. The skin over the area being treated will be cleaned.


Short-wave diathermy uses a rapidly alternating electrical field. Microwaves generally do not penetrate tissue as deeply as short waves. Both short-ware and microwave diathermy are considered electromagnetic treatment. If you have this treatment, an electrode drum is used to apply heat.


Towels are usually placed in layers between you and the unit. Treatments with electromagnetic heat last about 15 minutes and are given 2 to 3 times per day for 3 to 14 days.


Ultrasound heat treatments use high-frequency sound waves that cannot be heard by the human ear. Ultrasound heats a smaller area than shortwave diathermy. Muscle tissue, ligaments, and tendons absorb this form of energy very well. Fat absorbs heat to a much lesser degree. The effects of ultrasound heat treatment last about 1 hour.


Once the heat treatment has been completed, you will be checked for any symptoms of dizziness, nausea, or skin irritation.

What are the risks of deep heat treatment?

All heat treatments have the potential of tissue damage resulting from high temperatures. During ultrasound therapy, bony areas with little soft tissue (such as hand, feet, and elbow) can get too hot and cause pain and possible tissue damage. Exposure to the electrode drum during diathermy may produce hot spots. Short-wave or microwave diathermy signals may interfere with or damage a pacemaker.


Talk with your provider about whether this type of therapy is right for you.


Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.


HIA File EXR4113F.HTM Release 9.0/2006

Copyright © 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.

Copyright © 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.