A TENS machine is a small battery-operated  device that has leads connected to sticky pads 
called electrodes.

You attach the pads directly to your skin. When the machine is switched on, small electrical impulses are delivered to the affected area of your body, which you feel as a tingling sensation, which is not harmful with no side effects.

The electrical impulses can reduce the pain signals going to the spinal cord and the brain, which may help relieve pain and relax muscles. 

They may also stimulate the production of endorphins, which are the body’s natural painkillers. It can help to reduce pain and muscle spasms caused by a variety of conditions.

TENS is not for everyone to use. DO NOT USE it without first getting medical advice:

• If have a pacemaker or another type of electrical or metal implant 
in your body
• If you are pregnant, or there is a chance you might be pregnant – 
TENS is not recommended in early pregnancy
• If you have epilepsy or a heart problem
• If you have areas of numbness or sensory change in your body

It can help with:

• Arthritic pain

• Widespread pain conditions

• Most musculoskeletal pains

Does TENS work?

TENS is not a cure for your pain but it can give you short-term relief whilst the machine is on. It needs to be used for a maximum of 60 minutes at a time, usually up to three times a day. You must not fall asleep with the TENS machine on.

TENS is: • Non invasive • Relatively cheap • Patient controlled.

This is a general guide on how to use a TENS machine.

Always follow the manufacturer’s specific instructions.

TENS machine are small and lightweight, so you can use them while working or on the move. You can put it in your pocket, clip it to your belt or hold it in your hand. 

Positioning the pads

Make sure the machine is switched off before you attach the pads to your skin. Position the pads either side of the painful area, at least 2.5cm (1inch) apart. Never place the pads over:

• The front or sides of your neck

• Your temples

• Your mouth or eyes

• Your chest and upper back at the same time

• Irritated, infected or broken skin

• Varicose veins

• Numb areas

 

Turn on the TENS machine when the pads are attached in the correct places. You will feel a slight tingling sensation pass through your skin.

The machine has a dial that allows you to control the strength (intensity) of the electrical impulses.

Start on a low setting and gradually increase it until the sensation feels strong but comfortable. If the tingling sensation starts to feel painful or uncomfortable, reduce it slightly.

It may be helpful to first try this on an area where you do not have pain so you know what to expect the first time you try it.

Switch the TENS machine off after you have finished using it and remove the electrodes from your skin.

 

For most people, TENS is a safe treatment with no risks or side effects. Some people may be allergic to the pads and their skin may become red and irritated. Some people find the electrical impulse sensation uncomfortable.

Advice:

• DO NOT wear the TENS machine in the bath or shower

• DO NOT lend the TENS machine to other people

• DO NOT use the TENS machine during periods of strenuous activity

• DO NOT use over numb, broken, infected or inflamed skin

• DO NOT use over your genitals

• DO NOT use on the front or side of your neck

• DO NOT drive or operate heavy machinery with the TENS machine switched on

• DO NOT place the electrode pads to close to a medicine patch if you wear one

• DO NOT wear in bed, or fall asleep with it on - please ensure there is adequate airflow around the device • Avoid applying the TENS electrodes to the exact spot every day

• Do keep the TENS machine out of reach of children

• Do check your skin for signs of inflammation

• Do use the TENS before the pain becomes severe, it will be more effective

• Do place the electrodes at palms width apart

• Do continue with your usual medication.

TENS can cause burns and severe damage to your skin, if the electrical current is too high; the electrodes are placed on the wrong part of the body or too close together and if used for long periods without taking regular breaks from the therapy.

23-69 TENS electrode placement chart.JPG

23-69 © RNOH

Date of publication: December 2023

Date of next review: December 2025

Authors: Chronic Pain Team


Page last updated: 17 April 2025