TENS machines and Transcutaneous Electrical Nerve Stimulation

What is nerve stimulation?

Nerve stimulation is a technique that involves using an electrical current to relieve pain. More specifically, it is a technique for stimulating the nervous system by sending small, low-voltage electrical impulses to a specific nerve with the aim of modifying the way that neurons send signals. It is mainly used for treating pain.

Types of nerve stimulation

There are two types of nerve stimulation:

Transcutaneous nerve stimulation (or TENS, short for Transcutaneous Electrical Nerve Stimulation), which involves delivering electrical impulses via electrodes placed on the skin close to the painful area, or on a nerve pathway.

Percutaneous nerve stimulation (or PENS, short for Percutaneous Electrical Nerve Stimulation), which involves directly stimulating the targeted nerve(s), either by surgically implanting the electrodes under the skin, or by using electrodes in the form of acupuncture needles.

Transcutaneous Electrical Nerve Stimulation

Transcutaneous Electrical Nerve Stimulation (or TENS) is therefore a technique that aims to relieve pain by transmitting a low-voltage electrical current via electrodes placed on the skin. The electrical current in question is generated by a machine called a nerve stimulator, and for decades this technique has been used by healthcare professionals such as physiotherapists and chiropractors because it can provide non-invasive, drug-free relief from musculoskeletal pain.

TENS machines

A TENS machine, or nerve stimulator, consists of an electrical impulse generator connected to electrodes placed on your skin.

How do TENS machines work?

TENS machines stimulate the mechanisms responsible for sending pain signals by using small electrical impulses that are similar to natural bioelectricity. TENS machines work in three different ways:

  • They block the transmission of pain signals to the brain (by stimulating the nerves in and around the painful area to prevent the pain signal from being transmitted along the spinal cord)
  • They stimulate the production of endorphins (which are natural painkillers)
  • They improve the blood circulation (as the electrical impulses cause the muscle to contract and relax repeatedly), which helps to relieve tense shoulders, heavy legs, and cramps

It’s important to note that TENS machines are not a cure for pain, but they can reduce and relieve the pain in the short term.

When to use a nerve stimulator?

Transcutaneous Electrical Nerve Stimulation is recommended for muscle and joint pain, and for stiffness and numbness in the back, arms, shoulders, legs and feet. As nerve stimulators are small and lightweight machines, they can be used in everyday life, including at work.

Benefits and advantages of TENS machines

TENS machines provide a number of benefits:

Firstly, they offer a non-invasive, drug-free method of treatment.

Secondly, the treatment has virtually no side effects.

Finally, they enable the patient to receive individually tailored treatment and minimise discomfort, because the intensity, frequency and duration of the electrical stimulation can be adjusted.

Some machines, like OMRON pain relievers, also combine TENS with heat, thus reducing muscle and joint pain even more effectively.

References: (2018). Transcutaneous electrical neurostimulation (TENS). Retrieved from

Gonse, I. (2018). Electrodes to treat back pain. Retrieved from

Horde, P. Transcutaneous electrical nerve stimulation - indications and benefits. Retrieved from