Transcutaneous electrical nerve stimulation (TENS)
Transcutaneous electrical nerve stimulation (TENS) is a method of pain relief that can help some people with long-term painful conditions.
A TENS machine is asmall, battery-operated device that has leads connected to electrodes.
You attach the electrodes to your skin using self-adhesive pads. 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.
The electrical impulses can block or reduce the pain signals going to the spinal cord and brain, which can help reduce or relieve pain or muscle spasm.
The electric currents can also stimulate the production of endorphins, which are the body's natural painkillers.
TENS may be able to help reduce pain and muscle spasms caused by a wide range of conditions including:
It's also sometimes used as a method of pain relief during labour.
For most people, TENS is a safe treatment with few or no associated side effects. However, its effectiveness in treating pain is based on individual experience rather than scientific evidence.
Does TENS work?
There isn't enough good quality scientific evidence to say for sure whether TENS is a reliable method of pain relief. More research is needed and a number of clinical trials for TENS are currently under way.
Clinical experience has shown that TENS works well for some people, but it depends on the individual and the condition. It's often recommended for people who are unable to tolerate pain-relief medication.
The amount of pain that can be eased by TENS and the length of time that pain relief lasts for can vary from person to person.
Some people have reported long-lasting pain relief after using TENS. However, this is rare and pain relief is usually only experienced while actually using the TENS machine.
When the TENS machine is on it usually helps relieve pain after about 40 minutes. However, some people notice an improvement sooner than this. The tingling sensation can also act as a pleasant distraction from your pain.
To get the most benefit from your TENS machine, it's important that the settings are adjusted correctly for you and your individual condition (see the advice below).
If you're thinking about trying TENS, it should be used alongside other treatments and lifestyle changes, such as pain-relieving medication, regular exercise and relaxation techniques. TENS is less likely to be effective if it's used on its own.
You can use a TENS machine without seeing a physiotherapist first. However, a physiotherapist will be able to assess your condition and make recommendations about how to use the TENS machine. This means the results are likely to be more positive. The assessment will be different for each individual and the recommendations for how to use TENS may be similar but not the same.
The physiotherapist will recommend a starting prescription for using the TENS machine. It’s important that you’re honest about how the electric current feels on your skin. If it feels uncomfortable, the physiotherapist can adjust it for you. Once you have a prescription that you feel comfortable with, you should stay with it.
If you find TENS effective, you can buy a TENS machine from a pharmacy. They range in price from about £10-£200, depending on the quality and functions offered. More expensive machines aren't necessarily any better than lower-priced ones, so it's a good idea to do some research before you buy.
How to use TENS
The information below is a general guide on how to use a TENS machine. You should always follow the manufacturer's specific instructions.
As a TENS machine is small and lightweight, you can use it while you're working or on the move. It's likely that you'll get more benefit from it by using it in this way. You can put it in your pocket, clip it to your belt or hold it in your hand.
Position the self-adhesive pads either side of the painful area, at least 2.5cm (1 inch) apart. Make sure the machine is switched off while you attach the electrodes to your skin.
Never place the electrodes over:
the front or side of your neck (this is where the carotid arteries are, which are the main blood vessels that supply your head and neck)
your mouth or eyes
your heart (on the left-hand side of your chest)
irritated, delicate or broken skin
When you turn the TENS machine on you'll feel a slight tingling sensation pass through your skin. The machine has a dial that allows you to control the strength 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.
You may find that the sensation starts to reduce as your body gets used to the effect. In this case, turn the current up slightly so that the tingling sensation feels strong again. It should always feel strong but comfortable.
Switch the TENS machine off after you've finished using it and remove the electrodes from your skin. You can use TENS throughout the day for as long as you like.
A TENS machine is a battery-operated device that delivers small electrical impulses to painful areas of the body
When you shouldn't use TENS
Do not use TENS if:
you have a pacemaker or another type of implanted electrical device fitted
you're pregnant, or if there's a chance you might be pregnant – unless you are using TENS for pain relief during labour
you have epilepsy or a heart rhythm disorder (check with your GP)
you experience an allergic reaction to the electrodes (it's possible to get hypoallergenic electrodes)
you have broken skin, varicose veins or recent scarring in the area where you want to place the electrodes
you're driving or operating machinery
you're in the bath or shower
You can use TENS while flying, but you should inform the airline first.
Back pain guide
Explore this guide for information about different types of back pain, ways of preventing it and advice on treatment