TENS

Transcutaneous electrical nerve stimulation (TENS) is a method of pain relief involving the use of a mild electrical current.

Overview

A TENS machine is a small, battery-operated device that has leads connected to sticky pads called electrodes. These electrodes are attached directly to the skin. When the machine is switched on, small electrical impulses are delivered to the affected area of the body, which can help to ease certain types of pain.

Mechanism of Action

TENS is thought to work in two ways. On a high pulse rate of 90-130 Hz (the normal method of use), the electrical impulses generated by the TENS machine interfere with and block pain messages sent to the brain. This is due to the gate control theory of pain. This proposes that there's a gate mechanism in the brain and spinal cord nerves (the central nervous system). When the gate is open, pain messages get through to the brain and we feel pain. When the gate is closed, these pain messages are blocked and we don't feel pain. TENS machines are thought to stimulate certain non-pain-carrying nerves and close the gate. In effect, the brain is busy dealing with the messages it receives quickly from the TENS machine, rather than the slower (more painful) pain signals that the body is receiving from elsewhere. It's thought that the electrical impulses stimulate the release of endorphins – the body's natural painkillers.

Uses

TENS may be able to help reduce pain and muscle spasms caused by a wide range of conditions including: arthritis, period pain, knee pain, back pain and sports injuries. It's also commonly used in labour to help with contractions.

Safety and Side Effects

TENS is safe to use and has no side effects when used according to the instructions. Some people may be allergic to the pads and their skin may become red and irritated, but special pads for people with allergies are available. TENS should not be used on the head, over the front or sides of the neck, over the heart, in the genital area, or over areas of numbness.

See Also

• Pain management
• Physical therapy
• Electrotherapy

References

TENS Resources
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