Does a TENS Unit Relax Muscles?

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Transcutaneous Electrical Nerve Stimulation (TENS Units) has become extremely popular for pain relief, recovery, and relaxation. It’s even been promoted as a muscle builder, but that might be a bit of a stretch.

Many people are wondering: Does a TENS Unit Relax Muscles? Yes, it does relax muscles!

In this article, we’re going to look at how transcutaneous electrical nerve stimulation (TENS) can treat pain, and answer the question of how does a TENS unit relaxes muscles. If you’ve been wondering whether or not you should purchase one of these high-tech recovery devices, then this article’s for you! 


Although it may be hard to believe, advanced civilizations throughout history have used various electrostimulation forms to aid in muscle relaxation and pain relief. 

Historical records have shown that the ancient Greeks and Romans had a medical tradition that involved standing on a rare “electric fish” by the beach. With enough exposure to these small shocks, patients reported decreased pain and increased healing. This was over 2,000 years ago!

Today, we’ve come a long way from stepping on mysterious fish, but we’re still applying the same principle. By applying small, targeted jolts of electricity to muscle groups and joints through the use of TENS devices, the user can significantly relieve pain and speed up the healing process. 

Does A TENS Unit Relax Muscles?

Relaxation by the Water

The FDA recently approved TENS units, and their cousins EMS units, for use as an in-home treatment for treating pain, relaxing muscles, losing fat, and even toning and firming “saggy” muscles. 

If you’re wondering exactly how a TENS unit, such as the HiDow TENS/EMS unit we reviewed here, relaxes muscles, you’re not alone. The first question that most people have when they first hear about these devices is, “how is shocking myself supposed to treat my pain?

Well, let’s take a look. 

How TENS Reduces Pain

Hidow TENS Unit

The primary use of TENS is as a pain reliever. Our bodies treat electrical stimulation a lot differently than other forms of pain (such as an impact). Once it senses the electricity arcing through the electrode pads, your brain realizes that the pain is constant and repetitive. 

Instead of sending pain signals to your brain, it does the opposite. Your brain releases endorphins and pain-blocking hormones to prevent your body from feeling pain in the area that’s being targeted. In doing so, your body also blocks the pain coming from any pre-existing inflammation, pinched nerves, or injuries in the area! 

Essentially, the TENS is tricking your brain to not feel pain in the area. 

How TENS Relaxes Muscles

Now that we’ve established how TENS prevents you from feeling pain, let’s discuss how a TENS unit relaxes the muscles. 

As the TENS unit sends electrical pulses through the area that’s in pain, it causes the muscles in between the electrodes to tense up and release with each pulse of electricity. Most TENS units allow the user to control the pulsing frequency and intensity, so you’ll have full control over how hard your muscle tenses. 

After a 30-minute TENS session, your muscles will have contracted and released hundreds of times. The resulting effect will feel as if you had spent a half-hour performing targeted stretching or received a deep tissue massage to the area. 

While it may feel a bit sore or uncomfortable immediately after (like with a percussion massage), the muscles will be considerably looser and more relaxed. Y

ou also may notice that your range of motion is greater than it was before using TENS! 

How TENS Speeds Up Recovery

In addition to blocking pain and relaxing your muscles, using a TENS unit can also speed up your recovery time. This means that you can spend more time in the gym or at work and less time lying in bed trying to recover! 

When we overuse or overstrain our muscles, tendons, and joints, the microscopic fibers that make them up develop microtears. In response to these fibers tearing or stretching, they become swollen and inflamed. This is supposed to reduce your range of motion and allow the area to heal so that you don’t do any long-term damage. 

However, the less you use the area, the stiffer and more painful it often becomes. That’s why stretching and light exercise are such an important part of physical therapy. 

By using a TENS unit on your injured joints and muscle groups, you’ll effectively stimulate the area, increase blood flow, and speed up your recovery. 

As your muscle tenses and releases, the movement improves blood circulation to the area. The fresh blood brings oxygen, which, in turn, decreases inflammation in the area and helps the muscle fibers heal a lot quicker than they otherwise would. 

How To Get The Most Benefit From Your TENS Unit

If you want to achieve better pain relief and muscle relaxation, then there are several practices that you should keep in mind while using your TENS unit to get the most benefit out of it. 

Use It While You’re Moving

The most important piece of advice we can give you is to move while you use TENS. If you’re just lying down in bed or sitting on a chair, the device is only going to be half as effective as it otherwise would. This is due to a phenomenon called muscle memory

Some areas of our body remain injured for so long because their “memory” keeps them in the same limited position. If you want to truly heal, then you’ll need to re-train your muscles and replace the old memory with a new memory that causes the muscles to position themselves in a manner that doesn’t cause pain. 

As your TENS unit pulses, it will gradually relax the muscles that you’re targeting. When you combine this with light, targeted exercises that utilize the area, you’ll be re-training the muscle to move the way it did before the injury occurred. 

Stretch While Using TENS

In addition to performing light exercise while using TENS, you should also stretch. Stretching will help release knots and loosen the muscles. This, in turn, will exponentiate the effect of TENS, allowing the pulses to penetrate deeper so that you can get more benefit out of a single session. 

Short Intervals Are Best

Don’t make the mistake of overusing your TENS unit! Overuse of a TENS unit can cause your muscles to become fatigued, which can lead to rebound tightness– where your muscle becomes even tighter than it was before. Unfortunately, this is our body’s natural defense mechanism. 

In order to avoid rebound tightness, you should pace your treatments. Always start off by performing short intervals and low voltage. As your body becomes more used to the treatment, you can increase the voltage and session time. 

Keep your Unit in Good Condition

If you don’t maintain your TENS unit, you’ll be constantly struggling to get a good contact with the pads. See our articles on cleaning your TENS pads and keeping them sticky in order to ensure your TENS/EMS unit will continue to help for years to come.