What is a TENS?

TENS is a safe, easy to use and drug free method of pain relief used by hospital pain clinics and in physiotherapy since the 1960's. TENS is an abbreviation of Transcutaneous Electrical Nerve Stimulation. The TENS Device is a small battery operated machine which produces pain relieving electrical pulses. Up to 8 self adhesive electrodes are applied to the skin and attached to the TENS unit with lead wires. The tiny pulses are then passed from the TENS unit, via the lead wires and electrodes, so that they are applied to the nerves which lie underneath the skin surface. The electrodes are normally positioned over, or around, the area of pain but other more advanced applications may often prove better.

How does a TENS machine work?

TENS works through 3 different mechanisms.

First, electrical stimulation of the nerves can block a pain signal as they travel from the site of injury to the spine and

upwards to the brain. If these signals arrive at the brain we perceive pain - if they are blocked en-route to the brain we do not perceive pain - this is known as 'closing the pain gate'. When using TENS to 'close the gate' we use Conventional Tens Mode. Conventional (or Continuous) TENS mode produces a gentle and pleasant 'tingling' under and between the two electrodes. The 'tingle' sensation helps to block the pain by closing the 'pain gate' and slowing down the painful nerve signals - this produces analgesia (numbness) in the painful area.


Secondly, the body has its own built in mechanism for suppressing pain. It does this by releasing natural chemicals called endorphins in the brain and spinal cord and these chemicals act as very powerful analgesics. When using TENS to help activate endorphins we use Burst Tens Mode. Burst mode produces a rhythmic pulse which should be strong enough to produce a 'twitch' in the muscles underneath the electrodes. This muscle 'twitch' helps to release the endorphins and enkephalins and also helps the pain 'switches' in the brain to be activated through muscular and reflex activity.

Finally, muscles which are in spasm, or have become short and hard as a result of long term hypertension, can produce much of the
pain associated with back related problems and arthritis. We can help these muscles to relax and soften by using the gentle massage effect of Modulated TENS Mode. Modulation (massage) mode produces a gentle and comforting massage effect which exercises problematic muscles and helps to reduce musculoskeletal pain.