What is the Difference between TENS and Interferential units?


Are you in the market for an electrical nerve stimulator device that can offer you much needed pain relief? In the course of your search for information, you may have come up with two options for your therapy: a TENS unit, and an Interferential unit. Understanding the difference between the two therapeutic machines can help you to select the device that will best help you to control your type of pain.

How the TENS Device Works

The TENS device (transcutaneous electrical nerve stimulation device) works by delivering controlled electrical pulses into the body of an acute or chronic pain patient. The electrical stimulation is delivered through small electrodes that are strategically placed on the patient’s body.


The placement of the electrodes is a vital part of the machine’s functionality as correct placement will ensure that the therapeutic properties of the TENS unit are allowed to affect only the areas that are painful. Spinal pain sufferers, for example, would have the electrodes placed directly onto the affected area or surrounding it in order to expand the treatment area.

The electrical nerve stimulation unit offers pain patients two forms of therapeutic relief by way of two types of system settings. The first setting is the delivery of a low frequency pulse that encourages the patient’s body to release natural painkillers – endorphins. The second setting is the delivery of a slightly higher frequency pulse that stimulates the affected nerves into altering the message of pain that is being sent to the brain; without having an effect on any other parts of the patient’s body, the new message will simply allow the patient’s perception of the pain to be reduced. TENS therapy is valuable to post-operative patients rheumatoid arthritis patients, neck pain patients, and bone and joint patients.

How Interferential Devices Work

Interferential therapy works by using a varying mid-frequency current that is delivered into the body through the electrodes that are securely and strategically placed on the patient’s skin. The electrical impulses that are passed into the patient’s body cause a massaging sensation in the areas where the electrodes are located.

Interferential therapy penetrates easily into the patient’s skin to provide direct electrical stimulation to the muscles that are injured. When this happens, the body releases a flood of endorphins that will assist the muscles in relaxing. Muscles that have been injured as a result of surgery or an injury will heal at a much slower rate if they are not afforded the opportunity to relax.

The nerves in our bodies are capable of making rapid adjustments to the sensations that they are feeling – which could mean that without a variable electrical pulse, the therapy is less effective as the nerves adjust to the steady pulse.

The Key Differences

In essence it may seem like the two electrical stimulation therapies are identical in nature; however, there are several key differences between the two.

  1. The frequencies that are used in the TENS unit are lower than those used in the interferential units. It is thought that the higher and variable pulse used in the interferential devices is able to penetrate the patient’s skin, reducing any initial discomfort that the patient may feel when the therapy begins.
  2. While a TENS device has two level settings, it delivers steady electrical stimulation through the electrodes; the interferential device, however, delivers a variable electrical stimulation pulse.
  3. There is a slight difference in the sensations that patients may feel during their therapy sessions. When operating correctly, the TENS device will provide a sensation of tingling or vibrating. The interferential device will provide a massaging sensation to the patients.
  4. Both devices are highly effective at reducing the pain and discomfort that pain patients experience; however, they are each effective at treating different types of pain.

Before you start therapy to reduce the intensity of your pain, you should be certain that you provide your medical professional with all of the information needed for him to make a determination as to whether or not electrical stimulation therapy will be an effective option for your condition. Electrical stimulation therapy is an excellent option for pain patients who, for one reason or another, may not be able to take prescription pain medications. Pregnant women and patients who use pacemakers should never use electrical nerve stimulation prior to consulting with their health professional.

Looking for a Tens Unit? Check out our Tens Unit Reviews.


About Andy

Andy writes for a number of health related sites but has always been fascinated by alternative medicine and home remedies. His deep interests in nature and the body's innate ability to heal itself (given the right condition) have lead him to a pivotal time in his life - and so, Holistic Home Fitness was born. While it's relatively new at the moment, Andy wants to build this site into a huge reference site for a more holistic approach to health and fitness.