TENS vs EMS: which one is aimed at pain?

You go looking for something to help with the ache in your back or your elbow, and two sets of letters keep turning up: TENS and EMS. Both come with sticky pads, both have a small unit with buttons, and both promise to do something useful with electrical pulses. Some boxes even print both on the front.

They aren't the same thing, and the difference matters if pain is what you're trying to deal with. One is aimed at the signals your nerves send about pain. The other is aimed at making your muscles work.

Two devices that look almost identical

On the outside, TENS and EMS units are close to indistinguishable. Each sends mild electrical pulses from a small unit into pads stuck on your skin. The hardware is similar enough that plenty of devices are sold as combined TENS and EMS units, with different programs for each.

What separates them is what the pulses are set up to reach, and so what you notice while one is running. That's the part the packaging rarely explains.

What TENS therapy is aimed at

TENS stands for Transcutaneous Electrical Nerve Stimulation. Put simply, it's mild electrical pulses delivered through pads on the skin, set to stimulate the nerves that carry sensation in that area rather than the ones that move your muscles. What you notice is a tingling or buzzing under and around the pads.

The point of that tingle is to change how much of the pain message gets through on its way to your brain. The usual explanation for how that works is Gate Control Theory, and we've written a plain-English explainer of it. The short version is that a competing signal can crowd the pain signal out, a bit like rubbing a knock on your shin.

What EMS is aimed at

EMS stands for electrical muscle stimulation. Its pulses are set up to reach the nerves that control your muscles, so the muscle under the pads tightens and releases on its own.

That makes EMS a muscle tool first. What it's used for, and how, is a subject of its own, and we've covered how EMS works separately rather than squeezing it in here.

The difference you can feel

This is the most useful thing to know if you've got a combined unit, or you're not sure which program you're on. The label on a setting tells you what it's meant to do. The sensation tells you what it's actually doing.

• TENS: a tingle, buzz or pins-and-needles feeling across the skin under the pads, while the muscle underneath stays relaxed.
• EMS: the muscle itself tightens and lets go, sometimes enough that you can see it move, on a rhythm you don't control.

Guidance on using TENS for pain generally describes turning the intensity up until the tingle is strong but comfortable, without making the muscle contract. So if a setting meant for pain is making your muscle jump, it isn't doing what TENS therapy sets out to do. Turn it down, and check the instructions for what that program should feel like.

It works the other way too. A muscle-contracting program isn't a stronger version of a pain program. It's a different job, aimed at a different target.

Which one is aimed at pain

TENS. It's the one designed around pain signals, and it's the reason TENS therapy has been used in physiotherapy for decades. EMS is designed around muscle, and pain relief isn't what it sets out to do.

It's worth being straight about what TENS therapy doesn't do, too. It turns the pain message down. It doesn't repair whatever is sending it, and how much it helps varies from one person, and one kind of pain, to the next.

If your back aches because of how you sit all day, TENS therapy can make the day more manageable, and the chair will still be there tomorrow. That's why it belongs alongside the unglamorous fixes, like these daily habits that help prevent muscle pain for desk workers, not instead of them.

When to get it checked first

Electrical stimulation is something to use on pain you understand, not a way to avoid finding out what's going on. See a GP or physiotherapist before reaching for any device if your pain:

• started after a fall, an accident or a heavy knock
• comes with numbness, weakness, or a limb that won't do what you tell it
• is getting steadily worse, or has changed in character
• keeps you awake, or stays the same whether you rest or move
• comes with a fever, swelling or redness you can't explain
• hasn't shifted after a few weeks of doing the sensible things

Before using any TENS or EMS device, read the instructions that come with it, including who shouldn't use one and where the pads should never go. If you're not sure it suits you, ask your GP or physio first.

The short version

• TENS and EMS both send electrical pulses through pads on your skin, and the devices can look almost identical.
• TENS therapy is aimed at the nerves that carry sensation, and its job is to turn down the pain signal on its way to your brain.
• EMS is aimed at the nerves that control your muscles, and its job is to make the muscle contract.
• You can tell them apart by feel: TENS is a tingle with relaxed muscles, EMS is a muscle tightening on its own.
• If pain is what you're dealing with, TENS is the one designed for it, alongside dealing with whatever is causing the pain rather than instead of it.

The Vibit Pulse is our TENS therapy device. It's wireless, so nothing connects the device to the EasyStick pads on your skin, and it has four modes and ten intensity levels, so you can find the setting that suits the pain you've got. It's the same technology physios use, made for home, and built for the back, neck, shoulder, elbow and knee.