Diathermy is a therapeutic technique that uses electric currents, such as radio and sound waves, to generate heat deep within the skin. The term “diathermy,” which means “deep heating,” helps relax muscles and joints, reduce inflammation and swelling, and improve blood circulation.

Electric currents flow when electrons move between atoms. Electric currents are not visible to the human eye because atoms are the smallest particles in existence. When electrons transfer between atoms, heat is produced. This process can be likened to a relay race, where atoms pass electrons like batons. Through this activity, atoms engage in a form of physical movement. Similar to how running with a baton generates body heat through exertion, the movement of atoms passing electrons generates heat.

Types of diathermy treatment

Diathermy treatments, which generate deep heat using various energy methods, can be classified into three main types:

  • Short-wave diathermy: This method delivers electromagnetic currents into your tissues, generating heat through short bursts or pulses of energy, similar to ocean waves. It is also referred to as radio-wave diathermy or high-frequency diathermy.
  • Microwave diathermy: This technique uses very small electromagnetic waves, similar to those in a kitchen microwave oven, to produce heat within your tissues.
  • Ultrasound diathermy: This approach sends sound waves into your tissues, causing them to vibrate and generate heat.

Another form of diathermy is surgical diathermy. This technique employs high-frequency currents to cut tissue or clot blood during surgical procedures.

Reasons for undergoing the procedure

A diathermy treatment may be appropriate for you if you:

  • Experience chronic pain, muscle stiffness, tension, or muscle spasms.
  • Would like to recover from a strain or sprain more quickly.
  • Would like to enhance blood circulation in a certain bodily part.
  • Be suffering from an inflammatory condition.

Consult a medical professional to determine whether diathermy treatment is a good fit for you.

Diathermy can be used to treat the following conditions:

  • Chronic pain
  • Stiff muscles
  • Muscle spasms
  • Sprains and strains
  • Arthritis
  • Fibromyalgia
  • Edema


The most common risk associated with diathermy treatment is a burn from the machine. The device generates heat within your tissues, and prolonged exposure in one area can lead to burns. To mitigate this risk, your doctor will monitor your treatment closely to ensure it is both safe and effective.

During the procedure, electric currents flow through your body, which can result in a painful shock if you come into contact with metal. Inform your doctor if you have any metal implants, such as a pacemaker, as metal can react adversely with the diathermy machine and cause injury.

Before the procedure

Prior to undergoing a diathermy procedure, your doctor will instruct you to remove all metal items from your body. This precaution is necessary because metal can interact with the diathermy machine. You’ll need to take off jewelry and clothing containing metal components, such as glasses, earrings, and pants with zippers. In some cases, you may be provided with a gown to wear during the procedure.

Depending on the treatment area, your doctor will have you sit or lie down on a specialized, metal-free chair or table. They will then position the diathermy machine near the targeted area on your body.

During the procedure

During a diathermy procedure, a machine delivers a high-frequency electric current to a specific part of your body.

The specifics of each diathermy procedure can vary depending on the type, including:

  • Short wave: Radio waves are passed beneath your skin by a short-wave diathermy machine using electrodes, which are two plates positioned on your front and back, respectively. Since the radio waves are contained in the plates, they remain in one place.
  • Microwave: A lamp-like, large, flexible applicator is used in a microwave diathermy machine. In order to treat the affected area of your body, your therapist will position the applicator in close proximity to your skin. The applicator will emit microwaves that will heat the tissues under your skin.
  • Ultrasound: This procedure is comparable to an ultrasound exam in that it involves applying gel to your skin and using an ultrasound probe to send sound waves beneath it. Your tissues vibrate in response to these sound waves, producing heat.

During a diathermy procedure, the machine does not heat your entire body like an electric heater would. Instead, it emits an electric current that activates atoms in a specific part of your body, causing electrons to move between atoms and generating heat in that localized area. This results in a sensation of warmth radiating from the treated area.

The duration of a diathermy procedure can vary depending on the type, typically lasting around 15 to 20 minutes. In cases of more severe symptoms, the procedure may require a longer duration.

Throughout the procedure, it’s important to relax and remain very still while the diathermy machine delivers heat deep into your tissues.

After the procedure

After a diathermy procedure, you may experience some changes due to the effects of the treatment. This might include:

  • A reduction in tension or pain.
  • Muscles at ease.
  • The temperature in the treated area is raised.
  • Swelling is reduced.
  • A greater range of motion and flexibility.
  • Faster recovery from sprains and strains.


Following most diathermy sessions, you can generally resume your regular activities immediately afterward. Depending on your specific condition, you may need multiple diathermy treatments. Your doctor will provide a treatment plan outlining the frequency needed to support your recovery.

Diathermy is commonly used as a complementary treatment and is often paired with other therapies like physical therapy.