Chronic pain conditions like osteoarthritis, rheumatoid arthritis, and fibromyalgia may be helped by a small, non-invasive, over-the-counter device that costs less than $50 and has few risks — yet the American College of Rheumatology (ACR) recently advised against doctors recommending it in new guidelines for treating osteoarthritis. Why?
The reason: Scientific research is lacking or various study results are too inconclusive to support a broad recommendation to use TENS (transcutaneous electric nerve stimulation). But if you’re in pain and other home remedies aren’t working, should you talk to your doctor about giving TENS a try?
First, we asked patients on our Facebook page about their experiences with TENS. Responses ranged from “I wouldn’t be without it” and “incredibly helpful” to “never sure if it has helped” and “did nothing but annoy me” — and even “hated it” and “makes things worse.” Anecdotally, patient results are all over the map as well.
We asked a pain researcher who’s studied TENS and a rheumatologist who was involved in the new guidelines from the ACR to weigh in on how TENS works and whether arthritis patients should try it.
What Is TENS and How Does It Work?
“Transcutaneous electrical nerve stimulation is the application of electrical current through the skin for pain relief,” says researcher Kathleen Sluka, PT, PhD, a professor of physical therapy and rehabilitation science at the University of Iowa.
The TENS device has been around for decades, and although it is not known exactly how the stimulation works, there are theories. “TENS activates our body’s own painkillers,” says Dr. Sluka, who has extensively studied TENS. “Specifically, it can release our natural opioids, endorphins, and enkephalins [another naturally occurring brain compound], and other chemicals to stop pain signals in the brain.”
Activating these chemicals, Dr. Sluka says, reduces pain signals in the central nervous system.
In addition, “TENS works best for activity-induced pain and should therefore be used when doing activities such as walking, chores, or exercise,” she says. “TENS is used as a method to control pain to allow people to be more active.”
How Do You Use a TENS Machine?
The small, portable device is fairly simple to use. “Electrodes are placed on the skin and connected to the battery operated unit; patients can be taught to place the electrodes in the appropriate locations and use the device at home,” says rheumatologist Sharon L. Kolasinski, MD, a professor of clinical medicine at the University of Pennsylvania in Philadelphia and the principal investigator for the ACR’s new guidelines.
Talk to your doctor to see what setting is right for you. “It should be used at the highest tolerable intensity that is not painful,” Dr. Sluka says. “We often call this intensity strong but comfortable.” At certain times, though, you may need to lay off the machine if it hurts.
“During bad flares, my skin becomes so tender that I can’t cope with the feeling of the sticky pads, let alone the stimulation from the machine, but for the most part, it’s one of my favorite ways to manage my pain,” Sophie R. told us on Facebook.
What Does TENS Feel Like?
“TENS delivers a tingling sensation that can vary in intensity depending on the device that delivers it and how the device is set,” Dr. Kolasinski says. “Units can be set to deliver bursts of pulses or set to deliver continuous sensation.”
How Long Does Pain Relief Last?
“TENS produces its greatest effects when the unit is on — at the time when the body’s natural painkillers are being released and reducing activity of pain-producing neurons,” Dr. Sluka says.
Anecdotal patient experience backs this up: “I find it very helpful in relieving muscular pain, but only as long it is on for,” Michael M. told us on Facebook. “There is no lasting effect once the TENS is turned off.”
Some people we heard from use TENS throughout the day, but others caution against extended use. “My husband puts it on when he dresses me, and it comes off at bedtime to be charged,” Elaine H. told us on Facebook. Steve M. told us, “It helps some but only temporarily. A couple hours at best, but relief is relief.” Brenda B. warns, “don’t overuse it too much; the muscles will not appreciate it.”
You may need to experiment to see what works for you, and how long. Some research has shown that people may develop a tolerance to it, so you might want to start off on a low frequency, or vary the types of frequencies you use.
What Kind of Conditions Does TENS Treat?
TENS can be used to treat many kinds of pain conditions, from chronic back pain to acute post-operative pain. “TENS is used in a variety of chronic pain conditions but the evidence is variable and inconclusive on just how effective it is for any given diagnosis,” Dr. Kolasinski says. “In osteoarthritis patients, TENS does not treat or alter the arthritis, but is aimed at reducing pain.”
TENS may also be used for inflammatory arthritis such as rheumatoid arthritis or ankylosing spondylitis, as well as chronic pain disorders like fibromyalgia.
“TENS should be considered for arthritic pain — it is inexpensive, safe and easy to use, and part of a self-management strategy for people with arthritis, fibromyalgia, and other chronic pain conditions that gives a person the ability to control their pain,” Dr. Sluka says.
Is TENS Just a Placebo Effect?
Could the benefits of TENS be due to a placebo effect, in which the patient believes that the treatment is helping, which in turn can help with pain management? “There can be a placebo effect with any treatment, and the placebo effect can be particularly important when you are evaluating a physical intervention like TENS [in scientific studies],” Dr. Kolasinski says.
Dr. Sluka says the effects of TENS go beyond the placebo. “Our recent study, just published in Arthritis and Rheumatology, shows that for for individuals with fibromyalgia, active TENS produces a greater effect than placebo TENS, and this is greater than no TENS,” she says. “The effects of all pain treatments, including TENS, combine the effect of the placebo with the active component of the treatment to reduce pain.” Read more here about the research on TENS for fibro.
What Studies Say About TENS
Overall, results are varied. “This mixed research is based on a number of studies that have not used adequate intensities, have not applied the TENS during activity, or did not measure the effects of TENS during the use of TENS; rather they measure sometime after TENS was turned off and no longer active,” Dr. Sluka says. “Many studies are also underpowered. A systematic review, done several years ago, examined the effects of TENS on osteoarthritis and showed that when all studies were considered there was not a clinically significant difference; however, when only studies that used adequate intensities were considered there was a clinically meaningful effect.”
Dr. Kolasinski agrees that the studies have not been structured well. “In general, studies of TENS have been of very poor quality. Studies have generally involved a relatively small number of patients and followed them over a relatively short period of time,” she says. “Studies are also heterogeneous, which means the way in which the electric current is delivered can vary from one study to another, making studies more difficult to compare. Furthermore, it is difficult to devise an appropriate control [in a randomized trial], something that would be similar but not deliver electrical stimulation that study participants could not tell from actual use of TENS.”
So, she says, some studies in OA have shown that TENS is ineffective; others have shown some effect in improving pain but that the changes were not statistically significant.
If the research simply hasn’t been good, why are the ACR guidelines actually against recommending TENS?
“Since the last guideline for OA management was published in 2012, there have been more studies published looking at the use of TENS,” Dr. Kolasinski says. “New studies have included combining TENS with ultrasound, heat, or cold and looked at comparing it to a variety of different interventions. Because more studies have been done that have failed to show conclusive evidence that TENS works for OA, the recommendation was changed from conditionally for the treatment to strongly against TENS.”
It’s important to note, though, that the new guideline only applies to treatment of osteoarthritis, not other kinds of arthritis or fibromyalgia; even so, “the evidence is weak for all uses of TENS,” Dr. Kolasinski says.
Precautions and Reasons to Not Use a TENS Machine
Even with weak evidence supporting its pain relief benefits, TENS has very little risk, so in general it won’t cause harm. “Potentially, use of any electrical device could cause a shock if it is inappropriately used; however, there are no widespread reports of harm from TENS,” Dr. Kolasinski says. “TENS in widely used and devices are readily available, so it will obviously be possible to use it without evidence that it works.”
Some people shouldn’t use TENS, though, including those who have a pacemaker or other implanted electronic or metallic device. Before purchasing a device, make sure your doctor knows and can advise you on any health reasons why you potentially shouldn’t use one, such as pregnancy, cancer, diabetes, or certain other conditions.
Other Pain Relief Treatments With More Evidence
People with arthritis and fibromyalgia should know, though, that there are some other home remedies with more scientific support behind them, including:
- Tai chi
- Self-management programs
- Hot and cold therapy
- Topical and oral NSAIDs
“There is very good evidence that using a whole variety of exercises is helpful in treating osteoarthritis,” Dr. Kolasinski says. “There is also good evidence for participating in tai chi or yoga, attending self-efficacy and self-management programs, and using medications like topical and oral nonsteroidal anti-inflammatory drugs [NSAIDs]. There is evidence for the use of local heat and cold delivered in a variety of ways, from hot and cold packs to paraffin baths.”
Exercise, both strengthening and aerobic, have good studies to support their effects not only to increase function but also to reduce pain, Dr. Sluka says. “Exercise activates the body’s natural painkillers in the nervous system to stop the pain signals,” she says. Chronic pain affects the immune system, she says, causing more chemicals called inflammatory cytokines that promote pain, and less chemicals called anti-inflammatory cytokines that reduce pain. “Exercise normalizes this by increasing anti-inflammatory cytokines and decreasing inflammatory cytokines,” Dr. Sluka says.
TENS may actually be particularly useful coupled with an exercise regimen. “When applied at the appropriate doses with adequate intensities, TENS reduces pain during activity,” Dr. Sluka says. “TENS has the ability to be combined with exercise to reduce movement-evoked pain that occurs during activity, to allow people to exercise with less pain.”
Overall, despite the weak evidence from scientific studies, many patients say they’ve found relief from TENS. “I use mine all the time for my osteoarthritis pain in my knee and my fibro pain,” Cathy B. told us on Facebook. “It works really well and takes the swelling and inflammation down as well as the pain.” But talk to your doctor or physical therapist before starting TENS, and don’t replace your usual medication regimen with it. It may not work for you, but it most likely can’t hurt to try.
Not Sure What’s Causing Your Pain?
Check out PainSpot, our pain locator tool. Answer a few simple questions about what hurts and discover possible conditions that could be causing it. Start your PainSpot quiz.
ACR: Draft OA Guidelines Stress Non-Drug Tx, Leave Opioid Door Open. MedPage Today. https://www.medpagetoday.com/meetingcoverage/acr/83343. November 14, 2019.
Alternative Methods to Help Manage Pain After Orthopaedic Surgery. American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/treatment/alternative-methods-to-help-manage-pain-after-orthopaedic-surgery.
Bjordal JM, et al. Short-term efficacy of physical interventions in osteoarthritic knee pain. A systematic review and meta-analysis of randomised placebo-controlled trials. BMC Musculoskeletal Disorders. June 2007. doi: http://dx.doi.org/10.1186/1471-2474-8-51.
Brosseau L, et al. Transcutaneous electrical nerve stimulation (TENS) for the treatment of rheumatoid arthritis in the hand. Cochrane Database of Systematic Reviews. April 2003. doi: https://doi.org/10.1002/14651858.CD004377.
Dailey DL, et al. A Randomized Controlled Trial of TENS for Movement‐Evoked Pain in Women with Fibromyalgia. Arthritis & Rheumatology. November 2019. doi: https://doi.org/10.1002/art.41170.
Elboim-Gabyzon M, et al. Effects of transcutaneous electrical nerve stimulation (TENS) on acute postoperative pain intensity and mobility after hip fracture: A double-blinded, randomized trial. Clinical Interventions in Aging. October 2019. doi: https://doi.org/10.2147/CIA.S203658.
Dailey DL, et al. Transcutaneous Electrical Nerve Stimulation (TENS) reduces pain, fatigue, and hyperalgesia while restoring central inhibition in primary fibromyalgia. Pain. November 2013. doi: http://dx.doi.org/10.1016/j.pain.2013.07.043.
Exercise to treat chronic pain. University of Iowa Hospitals & Clinics. https://uihc.org/health-topics/exercise-treat-chronic-pain
Transcutaneous electrical nerve stimulation (TENS) for chronic pain ‐ an overview of Cochrane Reviews. Cochrane Database of Systematic Reviews. April 2019. doi: https://doi.org/10.1002/14651858.CD011890.pub3.
Gibson W, et al. Transcutaneous electrical nerve stimulation (TENS) for neuropathic pain in adults. Cochrane Database of Systematic Reviews. September 2017. doi: https://doi.org/10.1002/14651858.CD011976.pub2.
Interview with Kathleen Sluka, PT, PhD, professor of physical therapy and rehabilitation science at the University of Iowa
Interview with Sharon L. Kolasinski, MD, rheumatologist and professor of clinical medicine at the University of Pennsylvania in Philadelphia
Li J, et al. Transcutaneous electrical nerve stimulation for postoperative pain control after total knee arthroplasty. Medicine. September 2017. doi: http://dx.doi.org/10.1097/MD.0000000000008036.
Transcutaneous Electrical Nerve Stimulation (TENS). Michigan Medicine. https://www.uofmhealth.org/health-library/tr3497spec.
Transcutaneous electrical nerve stimulator (TENS). University of Iowa Hospitals & Clinics. https://uihc.org/health-topics/transcutaneous-electrical-nerve-stimulator-tens.
Vance CG, et al. Effects of Transcutaneous Electrical Nerve Stimulation on Pain, Pain Sensitivity, and Function in People With Knee Osteoarthritis: A Randomized Controlled Trial. Physical Therapy. July 2012. doi: http://dx.doi.org/10.2522/ptj.20110183.
Vance CG, et al. Using TENS for pain control: the state of the evidence. Pain Management. June 2014. doi: https://doi.org/10.2217/pmt.14.13.
Wai Ying KN, et al. Pain relief in osteoarthritis and rheumatoid arthritis: TENS. British Journal of Community Nursing.September 2013. doi: https://doi.org/10.12968/bjcn.2007.12.8.24366.