Systemic pain and TENS units: what a TENS unit does and does not do

What does systemic pain mean here?

On this page, systemic pain means pain that is spread over more than one part of the body. It often goes with long-term conditions. The University of Iowa Health Care page lists arthritis or other joint pain, fibromyalgia, muscle pain and neuropathic pain among the types of long-term pain for which a TENS unit “may be used.”

The NHS also lists “pain caused by a condition like arthritis or endometriosis.” NCCIH reports that among people with chronic pain who have a diagnosed problem, “the most frequent conditions are low-back pain or osteoarthritis, according to a national survey.” Read more about chronic pain in our glossary.

Can a TENS unit relieve pain all over the body?

No. A TENS unit works where the electrode pads are placed. The federal rule, 21 CFR 882.5890, describes a TENS device as one used “to apply an electrical current to electrodes on a patient’s skin to treat pain.” The current goes through the skin under and between the pads.

The NHS says to place the pads “near the painful parts of your body.” The University of Iowa Health Care page describes a package with four electrode patches, so a unit covers a limited area. For widespread pain, your clinician may choose one or two areas that bother you most and plan around those. A TENS unit may be one part of a wider plan, with movement and other care.

What do the studies say about distant effects?

A 2022 review in the journal Medicina notes a finding in people with fibromyalgia (FM) and osteoarthritis: “there is a reduction in pressure pain thresholds not only at the site of TENS stimulation but also at sites outside the area of application.” That is a lab measure from research. It does not mean a TENS unit relieves pain in the whole body. The same review concludes that TENS “may have efficacy for a variety of acute and chronic pain conditions, although the magnitude of the effect remains uncertain due to the low quality of existing literature.”

Which long-term pain conditions do sources name?

Sources name several conditions. None of them promises a result.

The NHS adds, “TENS does not work for everyone.” If you are not sure what causes your pain, the NHS says to “see a healthcare professional before using a TENS machine.”

What should I know about numb skin and neuropathy?

Check your skin before every session. Many people with nerve pain also have areas of changed feeling. The NHS says: “Do not use TENS on irritated, broken, infected or numb areas of skin.” The University of Iowa Health Care page lists “Skin that does not have normal sensation (feeling).”

Read the glossary entry on peripheral neuropathy to learn the term. Then ask your clinician where, if anywhere, pads are safe for you. Do not place pads on a numb area to “test” it.

What does Medicare say about this area?

The Medicare TENS policy, local coverage determination (LCD) L33802, does not name systemic pain. As of the revision effective January 1, 2024, it says “A TENS is covered for the treatment of beneficiaries with chronic, intractable pain or acute post-operative pain when one of the following coverage criteria, I or II, are met.”

The policy also lists headache and chronic low back pain as conditions that are not covered. If your widespread pain includes those, read our pages on back pain and head and neck pain. For other plans, check with your plan. Our insurance coverage guide explains the usual steps.

What can I do alongside a TENS unit?

Your clinician may suggest movement, stretching or therapy. The University of Iowa Health Care page says TENS helps most during activities such as walking, doing chores, or exercise. Our posts cover gentle options: full-body mobility exercises for beginners, stretching regularly and the benefits of mobility exercises.

Read our guide on pain management without opioids for other options to discuss. Never change a medicine on your own.

How do I use a TENS unit safely?

Follow your clinician’s instructions and your device’s instructions. Do not use a TENS unit if you have a pacemaker, if you have epilepsy, or if you are pregnant unless your doctor tells you to, as the NHS says. Read the full list in our TENS unit safety guide.

Next step

Talk with your doctor or physical therapist about which areas matter most and whether a trial fits you. To ask AHC a question, call (800) 749-1188 or use Contact. Our guide to TENS units explains the basics.

This page gives general information, not medical advice. Talk with your doctor or physical therapist about your own care, and follow your clinician's and your device's instructions. In an emergency, call 911.