--- title: "TENS Unit Settings Explained: Intensity, Rate, Pulse Width" description: "TENS unit settings explained in plain words: what intensity, frequency and pulse width mean, how strong to go, and what to ask your clinician." url: https://analgesic.multisites.ai/guides/tens-unit-settings-explained publisher: Analgesic Healthcare phone: +1-800-749-1188 contact: https://analgesic.multisites.ai/contact --- Guide # TENS unit settings explained: intensity, frequency and pulse width A TENS unit has three main settings: intensity (how strong), frequency (how many pulses each second) and pulse width (how long each pulse lasts). Sources say intensity should feel strong but comfortable, not painful. Your clinician and your device's manual set the rest. Follow your clinician's and your device's instructions. Updated October 26, 20267 min read5 sources ## Strong but comfortable University of Iowa Health Care says to set intensity to strong but comfortable. It should not hurt. ## Intensity matters A 2022 review of the evidence says stimulation intensity has been documented as critical to therapeutic success. ## No one setting fits all Frequency and pulse width differ by device and by person. Your clinician and your manual give your settings. ## Write it down A short log of settings, use and results helps your clinician adjust your plan. ## What do the settings on a TENS unit control? Most TENS units let you change three things: how strong the pulses feel, how often they come, and how long each pulse lasts. A [TENS unit](https://analgesic.multisites.ai/glossary/tens-unit) sends mild electrical pulses through [electrode pads](https://analgesic.multisites.ai/glossary/electrode-pad) on your skin to relieve pain. Setting Plain meaning Glossary Intensity How strong the pulses feel [Stimulation intensity](https://analgesic.multisites.ai/glossary/stimulation-intensity) Frequency (also called rate) How many pulses the unit sends each second [Pulse frequency](https://analgesic.multisites.ai/glossary/pulse-frequency) Pulse width (also called pulse duration) How long each single pulse lasts [Pulse width](https://analgesic.multisites.ai/glossary/pulse-width) Your device may use other names or fewer controls. Some units have preset programs. Read your manual to see which controls yours has. This guide explains what the settings mean. It does not give you a personal setting. Follow your clinician’s and your device’s instructions. Read the [TENS unit safety guide](https://analgesic.multisites.ai/guides/tens-unit-safety) before you start. ## How strong should the intensity be? Set intensity to strong but comfortable. It should not hurt. University of Iowa Health Care (UI Health Care) says: “Start treatment and change the intensity to be strong but comfortable.” The NHS gives the same direction in other words. It says to turn the dial slowly until you feel a tingling sensation, and that “It should not be painful.” Intensity matters. A 2022 review in the journal Medicina, “Using TENS for Pain Control: Update on the State of the Evidence,” says “stimulation intensity has been documented as critical to therapeutic success.” UI Health Care adds that turning the unit up so that you barely feel it will not give pain relief, according to research it cites. Here is how to read the feeling: What you feel What it likely means What to do Barely anything Intensity may be too low, or a pad or wire may be loose Turn the unit off. Check pads and wires. Then raise intensity slowly Tingling, tapping or buzzing UI Health Care lists these as normal feelings Keep the intensity strong but comfortable Muscle twitching that is not uncomfortable UI Health Care says this is OK Do not leave muscles twitching for longer than 30 minutes, since that may tire or sore them Pain or discomfort Too strong, or a problem with a pad Turn the unit off. Call your health care team if it happens again ## Why does the feeling fade, and what should I do? The feeling can fade after a few minutes because your body gets used to it. UI Health Care says this is normal. It says to turn up the intensity to keep it “strong but comfortable.” Do not jump to a high number. Raise the dial a little at a time. If the unit feels strong enough to hurt, lower it. ## What are frequency and pulse width? Frequency is how many pulses come each second. Pulse width is how long each pulse lasts. The 2022 review says, “The parameters of pulse frequency and pulse intensity are adjustable and linked to TENS efficacy.” The review also describes how researchers label frequency: “TENS can be applied with low frequencies (LF), <10 Hz, high frequencies (HF), >100 Hz, or mixed frequencies (LF and HF).” Those are research labels, not a setting for you. They show that low, high and mixed frequencies all exist. Some details to keep in mind: - The review reports the settings used in single studies. Those values are not instructions for patients. - The review says systematic reviews commonly describe “limited reporting on TENS parameters.” That means the right values are still unclear in the research. - Ask your clinician which pulse width suits you, and use the setting on your own device. Ask your doctor or physical therapist which frequency and pulse width fit your pain. Follow your clinician’s and your device’s instructions. ## How long should one session last? Your clinician or your device sets the plan. One source gives a time. UI Health Care says: “Research has shown that TENS is most helpful for chronic pain when used for at least 30 minutes while you are active.” It adds that TENS is less effective when you are sitting still, lying down or resting. UI Health Care also says you can take a break. It says 3 to 5 days off may be helpful. If your pain is at a manageable level, you may wait until a flare-up. Some people use TENS only when pain is most severe, and others use it daily. Do not wear a TENS unit while you sleep, bathe, shower or drive. The NHS and UI Health Care both say so. ## What do the modes on my device mean? Mode names differ by brand. Your manual lists your modes. Your clinician can tell you which one to use. If your device also lists words like EMS or NMES, those are different kinds of stimulation from TENS. Read the [TENS vs EMS, NMES and interferential guide](https://analgesic.multisites.ai/guides/tens-vs-ems-nmes-interferential) before you try them. ## What are common mistakes with TENS settings? Most mistakes come from rushing or guessing. Avoid these: 1. **Setting intensity too low.** UI Health Care says barely feeling it will not give relief. 2. **Setting intensity so high that it hurts.** Both sources say it should not hurt. 3. **Changing pads with the unit on.** UI Health Care says you can get shocked if you reposition or take off pads without turning the unit off first. 4. **Using a wet unit.** UI Health Care says you can get shocked if the unit gets wet. 5. **Ignoring your plan.** UI Health Care says to follow the treatment program in your After Visit Summary. 6. **Skipping the clean skin step.** A loose pad can change the stimulation. 7. **Trying a new mode without asking.** Mode names differ by brand, and your clinician chose your plan for your pain. Ask before you change it. 8. **Sharing your unit.** UI Health Care says not to let others use your TENS unit, just as you would not let others take a medicine prescribed for you. If you do not get relief, UI Health Care suggests these steps in order: do not use the unit for 3 to 5 days, then try again; try a different setting; turn up the intensity to strong but comfortable; try changing the pad position. Call your health care team if you still cannot get relief. ## What should I write down for my doctor? Keep a short log. It helps your clinician adjust your plan. Medicare’s policy article for TENS (A52520) lists what a clinician records at the end of a trial: the length of time you have had the pain, how often you used the unit, the typical duration each time, and the results. A log of the same things makes your visit faster. What to write Example Date and time Tuesday morning Pad position Left side of low back, two pads Mode and settings As on your device display How long you used it Minutes Activity Walking, chores, resting Pain before and after Your own 0 to 10 score Problems Skin redness, headache, dizziness Bring the log to your next visit. The [TENS trial period guide](https://analgesic.multisites.ai/guides/tens-trial-period) shows how a clinician uses this kind of record. ## What is a safe order of steps when I change a setting? Turn the unit off before you touch anything else. UI Health Care says to turn the TENS unit off before you put on, move or take off the pads. The NHS says to start with the machine off and then use the controls to set the current. A simple order works for most people: 1. Turn the unit off. 2. Place or move the pads. 3. Turn the unit on at the lowest level. 4. Raise intensity slowly until it feels strong but comfortable. 5. Turn the unit off before you remove the pads. This order protects your skin and lowers the chance of a shock. The [pad placement guide](https://analgesic.multisites.ai/guides/tens-pad-placement-guide) covers where the pads go. ## Who should not change settings without help? Anyone with a health condition that affects TENS use should ask a clinician first. The NHS says not to use TENS if you have epilepsy or a pacemaker. UI Health Care says not to use it with a cardiac pacemaker, defibrillator, spinal cord stimulator or any implanted metallic or electronic device. It says to talk with your health care provider if you have cancer, diabetes, cognitive impairment or epilepsy, or are pregnant. A [contraindication](https://analgesic.multisites.ai/glossary/contraindication) is a reason not to use a treatment. Check the [TENS unit safety guide](https://analgesic.multisites.ai/guides/tens-unit-safety) for the full list. Never raise settings to “push through” pain. Stop and call your clinician instead. ## Does my plan or Medicare look at my settings? Medicare’s policy asks a clinician to watch how the unit works during a trial. LCD L33802 says: “The trial period must be monitored by the treating practitioner to determine the effectiveness of the TENS unit in modulating the pain.” Your settings and your log help the clinician do that. Read the [Medicare TENS coverage guide](https://analgesic.multisites.ai/guides/does-medicare-cover-tens-unit) for the rules. Private plans have their own rules, so check with your plan. ## Next step Ask your doctor or physical therapist to write down your settings and your plan, then follow it. If you have questions about getting a TENS unit, call Analgesic Healthcare at (800) 749-1188 or use the [contact page](https://analgesic.multisites.ai/contact). ## Questions people ask ### What settings should I use on my TENS unit? Use the settings your clinician and your device's manual give you. Both University of Iowa Health Care and the NHS say the feeling should be tingling or strong but comfortable, never painful. This guide gives no personal settings. Follow your clinician's and your device's instructions. ### How strong should my TENS unit be? University of Iowa Health Care says to set intensity to strong but comfortable. It also says turning it up so you barely feel it will not provide pain relief. The NHS says to turn the dial slowly until you feel tingling that is not painful. ### Why does my TENS unit feel weaker after a few minutes? University of Iowa Health Care says this is normal because your body gets used to the stimulation. It says to turn up the intensity to keep it strong but comfortable. Never turn it up so high that it hurts, and call your health care team if you have concerns. ### What is the difference between frequency and pulse width? Frequency is how many pulses the unit sends each second. Pulse width is how long each single pulse lasts. A 2022 review says pulse frequency and intensity are adjustable and linked to how well TENS works. Ask your clinician which values fit your pain. ### How long should I use my TENS unit each time? University of Iowa Health Care says research shows TENS is most helpful for chronic pain when used for at least 30 minutes while you are active. Your clinician or your After Visit Summary may give a different plan. Follow your clinician's and your device's instructions. ### What if my TENS unit gives me no relief? University of Iowa Health Care suggests resting the unit for 3 to 5 days, then trying again. It also says to try a different setting, turn up the intensity to strong but comfortable, or change the pad position. Call your health care team if you cannot get relief. ## Terms on this page - [Stimulation intensity](https://analgesic.multisites.ai/glossary/stimulation-intensity) - [Cardiac pacemaker](https://analgesic.multisites.ai/glossary/cardiac-pacemaker) - [Contraindication](https://analgesic.multisites.ai/glossary/contraindication) - [Pulse frequency](https://analgesic.multisites.ai/glossary/pulse-frequency) - [Chronic pain](https://analgesic.multisites.ai/glossary/chronic-pain) - [Trial period](https://analgesic.multisites.ai/glossary/tens-trial-period) - [Pulse width](https://analgesic.multisites.ai/glossary/pulse-width) - [TENS unit](https://analgesic.multisites.ai/glossary/tens-unit) - [NMES](https://analgesic.multisites.ai/glossary/nmes) - [EMS](https://analgesic.multisites.ai/glossary/ems) ## Sources 1. [University of Iowa Health Care: Transcutaneous electrical nerve stimulator (TENS)](https://uihc.org/health-topics/transcutaneous-electrical-nerve-stimulator-tens) 2. [NHS: TENS (transcutaneous electrical nerve stimulation)](https://www.nhs.uk/conditions/transcutaneous-electrical-nerve-stimulation-tens/) 3. [CMS Medicare Coverage Database: Transcutaneous Electrical Nerve Stimulators (TENS) - Policy Article (A52520)](https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=52520) 4. [CMS Medicare Coverage Database: Transcutaneous Electrical Nerve Stimulators (TENS) (L33802)](https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdid=33802) 5. [PubMed Central: Using TENS for Pain Control: Update on the State of the Evidence](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9611192/) Checked against the sources above on October 26, 2026. Coverage rules change, so check the linked page or your plan before you act. 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. ## Keep reading - [Does Medicare cover a TENS unit? What the rules say in 2026Sometimes. Medicare's local policy (LCD L33802) covers a TENS unit for chronic, intractable pain or acute post-operative pain when set rules are met. It says TENS for chronic low back pain will be denied as not reasonable and necessary. Headache is also listed as not reasonable and necessary. Coverage is never certain.](https://analgesic.multisites.ai/guides/does-medicare-cover-tens-unit) - [TENS pad placement guide: where to put your electrode padsPut TENS electrode pads on clean, dry skin near the painful area, with a gap between them, and turn the unit off first. Never place pads on broken or numb skin, the head, face, throat, or over the spine. Your clinician can show you the exact spots for your pain.](https://analgesic.multisites.ai/guides/tens-pad-placement-guide) - [TENS unit safety: who should not use one, where pads must not go, and when to stopTENS units are not safe for everyone. The NHS says not to use TENS if you have epilepsy, have a pacemaker, or are pregnant unless your doctor or midwife tells you to. University of Iowa Health Care says not to use it with any implanted device. Never use TENS while you sleep, bathe, or drive.](https://analgesic.multisites.ai/guides/tens-unit-safety) - [TENS vs EMS, NMES and interferential therapy: how they differA TENS unit is made to treat pain through electrodes on the skin. EMS and NMES units are made to contract muscles. Interferential therapy crosses two medium-frequency currents inside the tissue. Some devices offer more than one mode. Your clinician's written order tells you which one you should use.](https://analgesic.multisites.ai/guides/tens-vs-ems-nmes-interferential) - [The TENS trial period: what the first 30 days look likeA TENS trial is a test period before you decide to keep a unit. For chronic pain, Medicare's policy requires a trial of at least one month (30 days) and no more than two months, paid as a rental. Your clinician watches how it works. Other plans may differ, so check with your plan.](https://analgesic.multisites.ai/guides/tens-trial-period) - [Back pain and TENS units: what Medicare says and what to askA TENS unit sends mild pulses through pads near the painful area. Medicare can cover one for pain after surgery when its criteria are met, but its policy (L33802) denies TENS for chronic low back pain. Other plans set their own rules. Your clinician decides if a unit fits your back pain and where the pads go.](https://analgesic.multisites.ai/pain-areas/back-pain) ## Questions about your unit or a bill? Call toll free. For customer care, ask for extension 508. [Call (800) 749-1188](tel:+1-800-749-1188)[Pay invoice](https://ahcpatientservices.com/)