TENS Units provide non-pharmaceutical pain control which can reduce dependency on pain medications. They are easy for patients to manage and can be worn during everyday activities such as at work and during recreational activities. They are inexpensive and non-addictive.
They are safe and simple to use without the risks associated with surgery or heavy duty narcotic medications. Patients can think clearly without living in a “narcotic fog”, thereby living more actively and productively.
The electrical stimulation from tens machine relieves pain by stimulating peripheral nerves through what is termed the gate control mechanism. The gate control theory of pain suggests that in the spinal cord there is a control mechanism acting as a gate.
The Gate Control theory was first introduced in 1965 by Melzack and Wall in their Science article “Pain Mechanisms: A New Theory”.
The electrical impulses from TENS units, according to this theory, represent a non-noxious input. This input suppresses pain by closing the gate to incoming noxious input, such as pain from an arthritic back. If the gate is closed by non-noxious stimuli, such as that provided by TENS unit (transcutaneous electrical nerve stimuli), then the body will not be able to process the noxious stimuli and pain will be therefore reduced.
Here’s a more detailed explanation. There are two types of cells in the area of the spinal cord where signals come into. One is “inhibitory” and the other is “transmission”. Transmission cells are activated by incoming signals and when a critical threshold level is reached, pain starts as the gate opens and the brain receives those signals and processes them as pain. The job of the inhibitory cells is to inhibit activation of the transmission cells, thereby closing the gate and keeping it closed. The job of a TENS unit is to excite the inhibitory cells and close the gate.
Tens machine produce two different current frequencies below the pain threshold that are tolerated by patients. This way, they close the gate rather than open it.