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In 2019, 20.4% of adults had chronic pain, and 7.4% of adults had chronic pain that frequently limited life or work activities (referred to as high impact chronic pain) in the past 3 months. Chronic pain and high-impact chronic pain increased with age and were highest among adults aged 65 and over.
To make the right decision about effective therapies for reducing chronic pain, it’s important to understand how each method works and what results you can expect. TENS (Transcutaneous electrical nerve stimulation) is a drug-free therapy that is available to assist with chronic pain management.
The TENS device consists of a control unit, an electrical lead, and gel pads or metal plates applied to the skin. When turned on, the TENS device delivers a low voltage current through the electrode pads placed on the skin. This current activates non-painful sensory nerve fibers and creates a tingling sensation.
You can use it at a doctor or physiotherapist clinic. You can also hire or purchase a TENS machine to use at home.
The electric current from the TENS machines acts on both the peripheral nervous system (nerves extending to your limbs and skin) and the central nervous system (the brain and spinal cord) to reduce pain.
In the peripheral nervous system, TENS reduces pain through a mechanism called ‘gate control.’ The TENS current activates fast transmitting non-painful sensory nerves. This nervous input travels much faster than the slowly transmitted pain signals, reaching the central nervous system first. These signals compete with the painful nerve signals, preventing the pain signals from traveling to the higher pain centers of the brain[2].
TENS acts by releasing pain inhibiting chemicals in the central nervous system, including natural endorphins and serotonin, and reducing chemicals that otherwise elevate painful sensations. There’s also evidence that pain inhibiting activity occurs in the central cortex of the brain during TENS therapy.
For effective pain relief, a TENS device needs to be used for 30–60 minutes and can be used for up to 2 hours. It can be used several times a day, as needed.
TENS should not be used on broken or desensitized skin, over an area of infection, or in a malignant tumor.
Areas of the body where it is unsafe to use TENS include the head, the front of the neck, or the chest. You should avoid placing the electrode over the carotid artery.
You can use TENS, where the electrodes are placed on either side of the spinal column, but you should not place the TENS electrodes directly over the spinal column.
Patients who should not use a TENS machine include less than 36 weeks pregnant, patients with a cardiac pacemaker, or patients with epilepsy.
Most people will not experience side effects. However, there is a small risk of allergic reaction to the electrode pads. Overuse of the machine may lead to muscle soreness, and setting the intensity too high can produce discomfort and muscle twitching.
