The Pain Gate can also be shut by stimulating the release of endogenous opioids (endorphins, enkephalins, and dynorphins), which are pain-relieving chemicals naturally released by the body in response to pain stimuli. Opioids are a naturally occurring hormone in the body. They are released in response to an injury or physical stress to reduce your pain and promote a feeling of wellbeing. Much like Morphine, and related medications, your opioids have a similar chemical structure, which explains their strong painkilling effects.
Acupuncture and TENS machines stimulate the release of endogenous opioids. The opioids then inhibitthe transmission of pain signals in the substantia gelatinosa part of the spinal cord – what is often referred to as the spinal root part of the nerve. When using TENS to help activate opioids release we use a 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 opioids and also helps the pain ‘switches’ in the brain to be activated through muscular and reflex activity.
A great example of endorphin release is the natural ‘high’ that runners and other athletes experience after 30 minutes of sustained exercise. Much like exercise, the endorphin release stimulated by the TENS may take up to 30 minutes or more to take a noticeable effect. The “feel good” effect may last several hours before endorphin levels in the body need to be increased again.