TENS stands for Transcutaneous Electric Nerve Stimulation. This is a small device, about the size of a pack of cigarettes that runs on batteries. It attaches to the skin, above and below or surrounding the place where the pain is located, with adhesive electrodes. When turned on the device produces a tingling sensation that “distracts” the brain from the discomfort of acute or chronic pain. The pain messages are stopped from getting up to your head just like closing a “gate” on a fence, this is Gate Theory. When there is muscle spasm, the TENS unit causes super small muscle contractions tiring out the muscle allowing it to relax from fatigue. A person can use the device for a few minutes or up to an hour, depending on their pain and response to the treatment.
The relief can be felt for up to 2-3 hours after it is turned off. This lasting effect is partly due to the blocked pain messages, a more relaxed muscle area, and from the effects of endorphin and enkephalin hormone response. These hormones are better known as the “runner’s high” hormones one experiences after an intense workout. They are the body’s natural pain killers that are released after a strenuous workout or run.
The TENS unit typically has three settings: Constant, Modulated, and Burst. Constant has a consistent intensity that does not change at all throughout the entire time it is being used. The Modulated changes a little throughout the time by getting a little stronger then a little weaker in intensity every few seconds. The Burst setting is a strong “thump” like a base drum beating a few times per second. Each of these is effective in giving pain relief, depending on the patient’s response to these settings.
There are no contra-indications of using a TENS unit with any medication taken by mouth because it works on the outer part of the skin. The precautions to its use are if you are pregnant, have increased or decreased skin sensation or nerve sensitivity changes, current cancer, or use a pacemaker. It also should not be used over the heart, breast or head of any patient. Otherwise, the only side effects to using a TENS unit include reddening or drying out of skin if the electrodes are used on the same place for a long time or a decreased response to the program over time as your body gets used to the settings.
