Electrical Modalities – TENS

Have you ever accidentally bumped your shin into the edge of a table and found that rubbing the area helped with the pain? Have you ever heard of electrical modalities, such as TENS, and wondered what these devices can do for you in terms of treatment? TENS is a non-invasive modality that works to relieve pain, just like how rubbing helps to decrease the pain!

What is TENS?

Transcutaneous Electrical Nerve Stimulation, or TENS, is a method used by healthcare professionals to reduce and relieve pain symptoms that patients may experience with chronic pain, acute pain, or during labour. A TENS machine delivers low frequency and pulsed electrical current to stimulate the body’s nerves. This is achieved through different sized pads, called “electrodes,” that sit on the skin via adhesives or a water-based gel.

So how does TENS help reduce and/or relieve pain? There are 2 theories to explain how it assists with pain reduction:

• The first theory is called the Gate Control Theory of Pain. In our bodies, we have a messaging system where signals can get sent towards and away from the brain. With the help of the spinal cord prioritizing which messages are important – like pain messages – and which messages are not, the brain can send out signals to our muscles to act accordingly. So let’s think of the spinal cord as a “gateway.” When the gate is open, pain signals are able to travel all the way up to the brain. This means the brain will interpret this message as “pain” and make you feel like you are in pain. In contrast, when the gates are closed, pain signals aren’t able to reach the brain. This means that there will be no interpretation of pain and therefore, you will not feel pain. Using a TENS machine is one way of closing the gate. The electrical current in TENS stimulates “non-pain” nerve fibres; these are interpreted in the brain while simultaneously blocking the pain signals, resulting in a reduction of the pain perceived.
• The second theory focuses on the body’s ability to create pain-easing chemicals called endorphins. Endorphins naturally get released in the body when you experience pain or stress. With a TENS machine, it stimulates the body to create even more endorphins to block those pain signals from reaching the brain, therefore reducing the pain felt!

Who can use a TENS machine?

TENS is generally a very safe option for everyone! However, there are a few people who should not be using the machine or must check with their family physician or a physiotherapist prior to use:

• Women who are pregnant but are not in labour
• Anyone with metal or electrical implants (eg. pacemaker, cochlear implant)
• People with severe heart conditions (eg. severe heart disease, heart failure, arrhythmias)
• People with epilepsy
• People who have deep vein thrombosis (DVT)

• Any circulatory insufficiencies
• Areas of reduced sensation or numb areas
• Varicose veins
• Cancer
• People who have allergies to adhesives or water-based ultrasound gel

While using the TENS machine, you want to avoid certain areas:

• Open wounds or broken skin
• Irritated or infected skin
• Near sensitive areas: eyes, temples, mouth, front or side of neck, on head, near reproductive organs or genitals, chest, abdomen, chest and upper back at the same time
• Areas recently treated with radiation
• Directly on the spine

How to use a TENS machine?

A TENS machine will come with the small and portable machine itself, along with wires and electrodes. The machine can be adjusted for different intensities, frequency (how often), duration (how long), and what type (burst or continuous). These functions can be discussed with your family physician or physiotherapist to find the perfect setting for your condition. Be sure to turn off the machine prior to placing the electrodes on, prior to moving them, or while taking them off. Since TENS is running an electrical current through the body, turning it off will prevent the risk of getting shocked! When placing the electrodes on your skin, make sure that they have full contact with the skin, i.e., avoid placing them over bony areas like your ankle bone. It is important to place the electrodes at least one inch (2-3cm) from each other, on either side of the painful area, and avoid any overlap.

Once the machine is turned on, you will notice that the intensity will feel like it’s dropping off within a few minutes – this is normal! It’s a phenomenon called “accommodation.” What happens here is that your body gets used to the stimulus on your skin. This is similar to when you wake up in the morning and put on a t-shirt; at first, your body feels the stimulus of the fabric, but after a few minutes, you don’t notice it anymore. The same thing happens when you use the TENS machine – you start off feeling a tingling/buzzing sensation and eventually, it will feel less and less. At this point, you can turn it up slowly, but aim for a “strong, but comfortable” feeling, with no muscle contractions or twitching. TENS machines are usually used for 15-20 minutes.

Since these machines are super small and portable, it makes it easy to carry around! It is a great option to use in the home, when walking outside, during your daily activities, and even during exercises. However, avoid using the machine while operating a car or machine, in a bath or shower, or while sleeping. If you experience any skin irritation, such as itchiness, redness, a rash developing, stop using the machine. Additionally, if you experience any nausea, headache, or dizziness, speak with your family physician or physiotherapist to see if this machine is suitable for you.

At Boost Physiotherapy, we offer a variety of treatments that include the use of TENS machines. It’s important to note that an adjunct like the TENS machine will only provide short-term pain relief. There are additional treatment options available to further improve your symptoms, so talk with one of our physiotherapists to see what kind of treatment plan will benefit you the most! Every condition or injury is different, so it is important to consider other possible options. If you have any further questions concerning your injury or condition, book an appointment online or call us today at 587-635-5555 (South Edmonton) or 780-591-5555 (Stony Plain). Our physiotherapists will be happy to assist you in any way!