Tens stands for Transcutaneous electrical nerve stimulation. (Transcutaneous simply means through the skin)
A TENS unit is a small device that delivers low voltage electric impulses to the nerve endings, through electrodes placed on the skin, to stimulate the nerves for the purpose of relieving pain.
TENS may work by blocking pain signals to the brain and/or stimulating the production of endorphins (naturally occurring pain-relieving chemicals).
A portable, battery-powered TENS unit can be worn all day if required. It is small enough to wear clip on a belt or wear inside clothing. Two electrodes are placed on the body at the site of the pain or sometimes at a point that would be used in acupuncture (some TENS units have two channels with four electrodes). A very mild electrical current stimulates nerve endings, which may result in a reduction in pain.
TENS is often used to treat the pain of arthritis. Even when TENS is being used for the same type of pain, not everyone will have the same results. Some people obtain immense relief, while others find it ineffective. Some report partial pain relief and use it along with other treatments.
Studies on TENS have had conflicting results. As many have shown positive results as negative results. There is greatest chance of success if a physician or physical therapist instructs a patient on the proper use of the unit. A one-month trial period is usually recommended to evaluate the effectiveness of this treatment.
*The current from a TENS unit may interfere with a pacemaker.
TENS units are considered safe and are FDA approved. A tens unit should be used under the supervision of a physician or physical therapist.