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TENS Unit: What it is and What it Does

tens unit

A TENS unit (Transcutaneous Electrical Nerve Stimulation) is an alternative way to relieve acute or chronic pain. The battery-operated portable device for pain management has been gaining popularity in the functional fitness world in recent times as a home treatment for athletes and coaches. The TENS unit is usually recommended for temporary relief of musculoskeletal pain after engaging in sports and recreational activities. This makes it an ideal recovery tool for CrossFit and functional fitness entuhusiasts.

Although many doctors and patients swear by it, there’s still some controversy on whether it actually works or is mainly the result of a placebo effect.

The TENS Unit is also similar to another popular recovery item called the Compex. However, the two do differ from each other. The TENS Unit is used at the sensory level and does not cause muscle contraction. The Compex is  used more for strength training by sending signals to the motor nerve of the muscle causing it to contract and build muscle mass.

An intense TENS treatment has been as effective in treating neck pain associated with musculoskeletal disorders. Stimulation intensity and severity of symptoms are some of the factors that greatly contribute to the effectiveness of TENS treatment.

How Does it Work?

In a nutshell, a TENS unit sends low-voltage electrical impulses through the nerve fibers in order to prevent pain stimulus from reaching your brain. It also stimulates your body to release endorphins, your natural painkillers.

A TENS unit is small enough to carry around in your pocket. The box has wires with leads that you can attach to your skin. These are called electrodes and when you switch the unit on, it will send out the electrical pulses which manifest as a tingling sensation.

The machine works in two ways. First, the impulses aid in the reduction of pain signals being delivered to your brain and spinal cord. Consequently, your tense muscles will relax. Second, if used in low intensity, it can stimulate the production of endorphins. These mechanisms allow you to experience symptomatic pain relief.

tens unit

Who Can Use It?

One important thing to note is that TENS isn’t for everyone. You need to consult with your doctor prior to use because it may not be suitable for your condition. Nevertheless, it is more commonly used by people with the following conditions:

  • Back pain

  • Post-workout pain

  • Musculoskeletal pain due to arthritis and fibromyalgia

  • Painful muscle cramps caused by monthly period

  • Neck pain

  • Migraine headaches

  • Sports injuries

  • During the early stage of labor

The duration and frequency of use may vary, but a few times each day for around 15-20 minutes each session is ideal.

What are the Health Benefits?

Aside from pain relief, here are the other benefits of TENS:

  • There are no known side effects. Still, you should follow the correct directions when using it and make sure you are well-aware of the warnings by the manufacturer (e.g. do not use when there’s water nearby).

  • TENS is generally safe; it is also a sound option if you’ve exhausted all home remedies to relieve pain.

  • It decreases pain perception because the impulses block the pain signals.

  • Some models come with a massage feature. You can adjust the settings accordingly to help ease muscle tension and stress.

  • It can reduce muscle inflammation with proper stimulation. This will allow you to function better since swelling and inflammation can result in more pain and discomfort.

  • It is possible that rehabilitation will be much quicker especially if the pain is already debilitating and affects your daily activities.

  • TENS is non-invasive which is good news for those who aren’t big fans of needles and other invasive treatments.

  • It improves circulation and reduces muscle spasms.

  • TENS can help you sleep better. Without the pain to interrupt, you can have a good night’s sleep and therefore bust your stress and boost your mood.

  • It lowers your fatigue and exhaustion. Dealing with pain on a regular basis can easily tire you out. TENS helps stimulate your nerves and muscles to address fatigue.

    tens unit

What You Should Remember

  • Don’t overdo it. Just because it has positive effects on your condition doesn’t necessarily mean you should use it way too much.

  • You don’t have to discontinue your pain medications unless your doctor has recommended it.

  • TENS is not advisable if you are wearing a pacemaker, have a cardiovascular disease, or in the early stages of pregnancy.

  • Read the manual carefully.

  • Do not place the pads on an irritated and injured skin surface.

  • You can buy your own TENS machine without anyone’s recommendation, but it’s best to consult with your doctor first especially if the cause of your pain has not yet been identified.

Although an ongoing debates about the true efficacy of TENS continues, several studies have concluded that TENS does have a certain amount of effectiveness in relieving pain. Perception of pain, however, may vary from one individual to another.


The Rx Review is an independent fitness website, reporting on the Sport of Fitness, functional fitness news, The CrossFit Games, health and diet related information, and also provides reviews on sports performance products.