TENS: what it is, what it is for and how it is done

TENS is a physiotherapy method that uses electrical impulses to exert analgesic action on the nervous system, helping to treat chronic and/or acute pain, such as low back pain, sciatica or tendonitis, for example.

This type of treatment, also known as “transcutaneous electrical neurostimulation”, works by stimulating sensory nerves, allowing the activation of natural pain control mechanisms and the release of endogenous opioids, such as enkephalin, which has an effect similar to opioid medications.

TENS must be performed by a specialized physiotherapist, using different intensities of electrical impulses, according to the condition being treated.

What is it for

The TENS technique is mainly used to relieve acute and chronic pain, such as:

• Arthritis;
• Pain in the lumbar and/or neck region;
• Sciatica pain;
• Tendinitis;
• Bursitis;
• Dislocation;
• Sprain;
• Epicondylitis;
• Rheumatism;
• Fibromyalgia;
• Neck ache;
• Knee pain;
• Bone pain;
• Diabetic neuropathy;
• Pelvic pain caused by endometriosis;
• Pain after surgery;
• Pain caused by sports injuries;
• Pain caused by cancer.

Therefore, when performing TENS for these situations, it is possible to promote muscle stimulation and vasodilation, which favors the reduction of pain, swelling and the healing of soft tissue injuries.

Is TENS useful for relieving labor pain?

TENS can be used to relieve labor pain, especially low back pain, and is normally indicated when other forms of pain relief have not been effective, such as exercise, massage or breathing and relaxation techniques. See the main ways to alleviate labor pain.

In this way, TENS can be performed by the physiotherapist at any stage of labor, especially at the beginning of labor, and is considered a safe method if applied correctly, and without causing changes to the baby.

How it is made

TENS is performed by applying electrodes to the skin, connected to a device that sends electrical impulses, which activate internal control mechanisms of the nervous system, exerting an analgesic action. This is a non-invasive method, which is non-addictive, has no health risks and in most cases does not cause side effects.

Its physiological mechanism of analgesia depends on the modulation of the current applied to the affected region, that is, if low-frequency and high-intensity electrical impulses are applied, endorphins are released by the brain or spinal cord, which are substances with effects similar to morphine, thus leading to to pain relief.

If electrical impulses are applied with high frequency and low intensity, analgesia occurs due to a blockage of nerve pain signals that are not sent to the brain.

The application of TENS lasts around 20 to 40 minutes, depending on the intensity of the stimulus and can be done in an office by a physiotherapist or at home.

When it is not indicated

As it is a treatment method that involves the application of electrical current, performing TENS is not recommended for women who are breastfeeding or for people who have a pacemaker, cardiac arrhythmia, deep vein thrombosis or epileptic disorders.

Furthermore, the application should not be made along the path of the carotid artery or in areas of the skin that have changes due to the disease or changes in sensitivity.

During pregnancy, TENS should not be used in early pregnancy, in women with a history of epilepsy, uterine irritation, a history of miscarriage, or if there are complications in the current pregnancy. Additionally, TENS should not be done on the belly, pelvic area, hands, feet, legs, knees, shoulders, cheeks, or neck.