Lots of our patients ask us about TENS machines and whether they might be of assistance in their situations. So, lets go through what exactly is TENS, when can it be used, and how should you set up your machine to get good relief.
TENS stands for Transcutaneous Electronic Nerve Stimulation. If you do a search on the internet you will find a heap of different units that provide different types of sensory nerve stimulation electronically. When we are using TENS medically, we’re talking about a certain type of electrical current set at specific frequencies that have been researched and proven. So, not all TENS that you find on the internet are equal. It is best to buy from a medical centre or your physiotherapy clinic.
So do TENS machines work?
TENS machines work through 2 mechanisms – The Pain Gating Mechanism, and by stimulating the body’s production of natural pain killers – the Endogenous Opiod System.
The Pain Gating Mechanism works by inhibiting the pain messages. A simplified explanation is If you think of your nerves as a one way street – by stimulating the nerve with the tingling feeling of the TENS, this keeps the nerve busy and it can’t pass a pain message to the brain. The best settings to use TENS like this is on a high frequency – 90 to 130 Hz.
The Endogenous Opiod System is stimulated via different nerves, to activate the body’s own natural opiod pain killer system within the spinal cord, thereby providing pain relief. To use a TENS this way it needs to be set on a low frequency of 2-5Hz.
There is an alternative approach, using the burst setting on the TENS. By setting the machine to the higher 90 to 130Hz, but then bursting at a lower frequency, you can stimulate both the pain gating and endogenous opiod systems at the same time. This works well for a lot of our patients.
Everyone’s bodies are different and respond better at a range of frequencies. The above frequencies are a guide, but if using a TENS it is best to try different frequencies and find out what works best for your body.
When would you use a TENS?
If you have pain, and want to try a pain-relieving approach that is not pharmaceutical-based, or if your medically prescribed pain medications aren’t quite covering your pain. Often we prescribe TENS as a pain management tool, to enable you to complete movements or exercises or to give you a way of relieving your pain after aggravating activities.
Are there times when TENS is contraindicated (shouldn’t be used)?
- If you are unable to understand or follow the instructions of your physiotherapist.
- If you have a pacemaker.
- During pregnancy (although we use TENS during active labour).
- If over the front of the neck.
- Patients who have an allergic reaction to the electrodes or over a dermatitis/eczema site.
There are also precautions to treatment with TENS, so please consult your physiotherapist for an assessment of whether TENS would help in your situation, and how to correctly set up your machine. To book an appointment with one of our physiotherapists give us a call or book online through our website.