TENS therapy provides pain relief through two methods, pain gaiting and the release of endorphins.
Pain Gaiting
Electrodes send millions of impulses through the nerve endings into the spinal cord and brain, which effectively block the slower pain impulses from connecting. Pain signals have much smaller nerve diameters when compared to the pleasant impulses which cause them to be overridden by the size and capacity of the signals provided by TENS. This is similar to the body natural instinct to stop the pain. When you hit your elbow, you instinctively start rubbing the injured spot. This massage stimulates the nerves and creates pleasurable signals to overwhelm the pain.
The Release of Endorphins
Pain is also relieved by the release of hormones such as endorphins, which the body releases in response to an injury or stress. They are composed of a similar chemical structure to Morphine or other pain killing medications but are completely natural.
A TENS unit creates a pulsing rhythm that causes the muscles to “twitch” which allows the release of the endorphin hormone. For example, exercise also releases endorphins, which is why some people experience a “runners high." This feeling of pleasure is similar to the feelings produced by a TENS unit, which combat pain signals.