The Basics of TENS Units For Pain Management (Transcutaneous Electrical Nerve Stimulation)

T.E.N.S. is an acronym for Transcutaneous Electrical Nerve Stimulation. They are small battery powered devices designed to relieve post-operative, acute, and chronic pain. They are about the size of an iPod. It is a safe non-invasive drug free method of pain management that can help decrease the need for pain medication and also supplement treatment being received for pain control. It is used for pain caused by peripheral nerves and not centrally derived pain. TENS Units are prescription only devices. Sometimes they have attachments that go on your pants or pockets so that they are easy to bring with you.

TENS units are often used along with additional non-operative treatments such as Physical Therapy, Physiotherapy, Pain Management, Chiropractic, Spinal Decompression, or Manipulation Under Anesthesia.

How Do They Work?

A TENS unit is a device that transmits small square electrical pulses to the electrodes, which transmit this electrical pulse to the underlying nerves. The fundamental components of a TENS unit are the electrodes, a highly advanced computer chip, and an electrical battery source. The small amount of electricity is transmitted through the computer component then to the electrodes, which transmits the electrical waveform through the skin to the underlying nerves.

The user can personalize the pulse frequency, which is the strength of the electrical current given to the electrode (this should be accomplished in conjunction with the prescribing provider).Typically the prescribing provider will show the patient how to use the device and show any advisable setting options.

What conditions are helped with Transcutaneous Units?

Neck Pain, Back Pain, Arthritis, Sciatica, headaches, Muscular Strains, TMJ Disorder, Radiculopathy, pain from herniated discs, mid back pain, upper back pain, tendonitis, Sports Injuries, bursitis,

TENS units will not cure a disease or pain problem. They are of no curative value. It is a symptomatic treatment which suppresses pain sensation.

Application of a TENS Unit

Electrodes are placed on or near the area of pain. Soothing pulses are sent via the electrodes through the skin and along the nerve fibers. The current travels through the electrodes and into the skin stimulating specific nerve pathways to produce a tingling or massaging sensation that reduces the perception of pain. The pulses suppress pain signals to the brain. TENS Machines also encourage the body to produce higher levels of its own pain killing chemicals called Endorphins.

How long does it take for a TENS Machine to start working to relieve my pain?

It takes approximately 30 minutes or less to feel the effects. Some people use their TENS unit throughout the day off and on. It’s not typically recommended to be used continuously. Rather best to use for a period of time (1-2 hours) then take off for a while.

What does a TENS Machine feel like when it’s turned on?

The device produces a tingling sensation but should not be painful.

Who Should Not Use a TENS Unit?

  • Persons using a CARDIAC PACEMAKER
  • Has any form of malignancy,
  • Various conditions where circulation is impaired.
  • Persons with a heart condition.
  • By someone with epilepsy
  • Around the head
  • With the electrodes placed on the neck near carotid
  • It may not be used transcerebrally across the head,
  • Not over the carotid sinus(where the jaw meets the neck), over metal implants or in conjunction with sleep apnea or heart monitors.

You should be aware that TENS units provide symptomatic therapy only and are not considered curative.

What are potential adverse effects with using TENS Units?

Users of TENS machines experience significant pain relief by and large. Some patients note that their skin is red where the electrodes are placed.

How can I obtain a TENS Unit?

One needs a prescription from a medical provider such as a chiropractor or an MD/DO for a TENS Machine. When you receive a TENS Unit, the machine will be set to optimally manage your pain condition and personal instructions will be given on its use. One should not attempt to change the settings without having undergone this instruction.

Electrodes are attached to the surface of the skin over or near the area where you are experiencing pain. It is important that you learn how to:

-Correctly put on the electrodes -Operate the Unit -Change the Batteries -Vary the controls and Settings -Set the proper duration and intensity of the stimulation

How well do they work?

For some chronic and acute pain patients, a TENS machine provides pain relief that can last for several hours. For others, a TENS Unit may help reduce the amount of pain medication needed.

Research on TENS

Few quality research studies have been done on the use of TENS for pain relief. With regards to the literature that does exist, it’s controversial. Anecdotally however, patients often rave about the pain relief felt. In conjunction with physical therapy, chiropractic treatments, or pain management treatments, the results tend to be good to excellent. They also work well in the post-operative setting.


Despite the lack of hard scientific data backing up TENS unit efficacy, they are mainstream for pain control and extremely safe. Ask your doctor if a TENS will help your condition.