Transcutaneous electrical nerve stimulation (TENS) is a therapy
that uses mild electrical current to treat pain.
Current is delivered through small pieces of material that conduct
electricity (electrodes). These are placed on the skin near the source of pain.
When the current is delivered, some people experience less pain. This may be
because electricity from the electrodes stimulates the nerves in an affected
area and sends signals to the brain that "scramble" normal pain signals.
Another theory is that the electrical stimulation of the nerve may help the
body to produce natural painkillers called endorphins, which may block the
perception of pain.