TENS unit safety checklist: a printable list for pacemakers, pregnancy, skin and pad placement

What is the quick safety checklist for a TENS unit?

Use this list before every session, and print it if you like. Check each box. If you cannot check one, stop and ask your clinician.

A TENS unit sends mild electrical pulses through pads on the skin to treat pain. Follow your clinician’s and your device’s instructions. This page uses two sources: the NHS TENS page (last reviewed 14 February 2025) and the University of Iowa Health Care TENS page (reviewed January 1, 2019). It does not replace your clinician’s advice. Our main TENS unit safety guide gives more detail.

Who should not use a TENS unit?

Some people should not use TENS at all, and some need a clinician’s approval first. The NHS has a short list under “Do not use TENS if”. It names three cases: you have epilepsy, you have a pacemaker, or “you’re pregnant, unless your doctor or midwife tells you to”.

University of Iowa Health Care has a longer list. It says “Do not use TENS if you have:”

• “A cardiac pacemaker or defibrillator”
• “Spinal cord stimulator”
• “In-dwelling pumps or monitors”
• “Any implanted metallic or electronic device”

It also says to “Talk with your health care provider if you have” cancer, diabetes, cognitive impairment or epilepsy, “Or are pregnant.” Bring this list to your appointment.

What about a pacemaker or other implant?

Do not use TENS. Both sources say a pacemaker is a reason not to use TENS. University of Iowa Health Care extends this to defibrillators, spinal cord stimulators, pumps, monitors and any implanted metallic or electronic device. See the glossary entries for cardiac pacemaker and implanted medical device. If you have one, ask your doctor about other ways to manage pain.

What about pregnancy?

Ask your doctor or midwife first. The NHS allows TENS in pregnancy only when “your doctor or midwife tells you to.” University of Iowa Health Care puts pregnancy on its “talk with your health care provider” list. A contraindication is a reason not to use a treatment, and pregnancy is one the NHS names.

What about epilepsy?

The NHS says not to use TENS if you have epilepsy. University of Iowa Health Care says to talk with your health care provider if you have it. Because the two pages word it differently, treat epilepsy as a stop-and-ask item. Do not start without your clinician’s direct answer.

What about allergies?

University of Iowa Health Care says: “People who are allergic to nickel and/or adhesives may have skin irritation with TENS.” The NHS says a healthcare professional “can also tell you about alternatives if your skin is sensitive to the sticky pads.” Tell your clinician about any allergy before your first session.

Where should I never place TENS pads?

Do not place pads on skin that is not healthy, or on the head, face or throat. The two pages give these lists.

One list has items the other lacks. Follow the stricter result: if either source says not to, do not. University of Iowa Health Care also says the pads “should not touch each other or any metal object, such as a belt buckle or metal jewelry.” If you wonder about the neck, see our neck, shoulder and headache guide. For general placement rules, see our pad placement guide.

When should I never use TENS?

Do not use TENS while you sleep, bathe, shower, drive or use machinery. The NHS says: “Do not use TENS while you sleep”, “Do not use TENS in the bath or shower” and “Do not use TENS when driving or using tools or machinery”. University of Iowa Health Care lists the same four under “Do not use TENS while:”.

Their reasons are simple. For sleep, University of Iowa Health Care says “It is easy for the wires to get tangled or unplugged, or the patches may come off.” For water, it says “There is a chance for electrical shock since it is an electrical device. Also, the unit is not waterproof and would be damaged.”

What should I do to stay safe during a session?

Turn the unit off whenever you touch the pads or wires. University of Iowa Health Care says: “Turn the TENS unit off before you put on, move, or take off the electrode patches.” It lists these steps for your protection:

1. Turn the unit off before you place, move or remove pads.
2. Do not share your pads with other people.
3. Only use the TENS unit on yourself as instructed.
4. Keep the unit out of the reach of children.
5. Use the TENS unit on clean, dry skin so the patches make firm contact.

The NHS says: “Turn the dial slowly until you feel a tingling sensation. It should not be painful.” University of Iowa Health Care says to set the intensity to “strong but comfortable.” Never turn up the dial to the point of pain.

What are the shock risks?

You can get shocked if you do not follow the steps. University of Iowa Health Care says you can get shocked if “You reposition, or take off, the patches or if you remove the wires from the patches without first turning the unit off”, if “The unit gets wet while you are using it”, or if “You touch bare wires on a damaged cord.” Check wires for damage. Put lead wires “all the way into the connector on each patch” so no bare metal pins are exposed.

What about other medical equipment?

University of Iowa Health Care warns: “Electronic equipment, such as EKG monitors and EKG alarms, may not work the right way when TENS is in use.” Tell your care team that you use TENS before any exam or test.

When should I stop using TENS?

Stop and talk with your clinician if you notice any of these. University of Iowa Health Care says to “Stop using TENS and talk with your doctor or health care team” if you have skin irritation (redness, rash, itching), headache, dizziness or nausea.

The NHS says: “If your skin becomes itchy, irritated or red (redness may be harder to see on brown or black skin), turn off the machine and remove the pads.” For help with sticky or slipping pads, see our electrode pads and supplies guide. The glossary explains skin irritation.

What should I do if the unit does not seem to work?

Turn the unit off first, then check the basics. University of Iowa Health Care lists these checks if you cannot feel the current: check the power source, check that every patch is sticking to the body, and check that the wires are plugged into the patch and the unit properly. If a wire comes out of the unit or a patch, “Turn the unit off, put the wire back in, and restart the unit.”

If you feel no pain relief, the same page says: “Do not use the unit for 3 to 5 days. Then try it again.” It also says to try a different setting or a new patch position, and to “Call your health care team for help if you cannot get relief.” Do not move pads onto the head, face or throat, and do not raise the intensity to the point of pain. Follow your clinician’s and your device’s instructions.

What should I tell my care team before I start?

Share your full health history, since the lists above are not complete. The NHS says: “If you want to try TENS for pain relief, it’s a good idea to check with a GP or other healthcare professional first, to make sure TENS is safe for you.” It also says: “If you’re not sure what’s causing your pain, see a healthcare professional before using a TENS machine.”

Bring these items to the visit:

• Your list of medicines and any implanted devices, including a pacemaker or defibrillator
• Whether you are pregnant or could be
• Any history of seizures
• Allergies to nickel or adhesives
• Any skin problems, numb areas or open wounds near where the pads would go
• Your device, its manual and its pads

The NHS also says: “There are some things you should not use TENS for. Read the leaflet that comes with your machine for the full list and for further information about how to use TENS.” A device leaflet may list more limits than this page does. Read it, and ask if anything is unclear.

How often can I use a TENS unit?

Your clinician decides, and no single rule applies to everyone. University of Iowa Health Care says: “Some people use their TENS only when their pain is most severe, while others use it daily.” It adds that “3 to 5 days off may be helpful.” Follow your clinician’s and your device’s instructions for how long each session lasts.

Next step

Take this checklist to your doctor or physical therapist and go through it together. Then call AHC at (800) 749-1188 or use contact.

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.