Does TENS Help to Decrease Pain?

Electrical stimulation applied to a woman's rotator cuff.
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Transcutaneous electrical neuromuscular stimulation, or TENS, is a form of electrical stimulation that has been used for years as a physical therapy modality to help patients control pain. It is considered a passive modality; you do nothing while the TENS is working. But how does TENS work, and does it really work to control your pain?

Physical Therapy for Pain Relief

If you're having pain that limits your normal functional mobility, your doctor may refer you to a physical therapist to help reduce the pain. You may be asked to perform exercises or to change your posture to help your condition.

Your physical therapist may also use a variety of physical agents or modalities, like electrical stimulation, ultrasound, or heat and ice to help control your pain. While these treatments are commonly used in therapy, there's some question as to their effectiveness in helping to decrease or eliminate pain.

How is TENS Applied to the Body?

A TENS unit is a small handheld device. There are usually two lead wires that connect to the device, and two small electrodes at the end of each lead wire. The electrodes are adhesive, so they can stick to your skin.

To use a TENS unit, you must place the adhesive electrodes on your skin. Typically, placement of the electrodes is directly over or near the site of your pain. Ask your physical therapist where to place the electrodes on your body.

Once the electrodes have adhered to your skin, you can turn on the TENS unit and adjust the intensity of the electrical pulses to suit your needs. Again, advice from your physical therapist is needed to ensure that you set your TENS unit to the proper intensity for your specific condition.

How Does TENS Work?

There are two theories that describe how TENS helps to modulate pain in your body: the gate theory and the opiate theory.

The Gate Theory. Pain signals from your body to your brain travel along specific nerves. Your brain processes these signals and then formulates the idea that something hurts; you then feel pain.

Imagine that these signals must pass through a gate to get to the brain and that this gate allows only one signal through at a time. It's theorized that you can use the tingling sensation from TENS to go through the gate instead of the painful signal from your body; this helps to reduce or eliminate the pain that you are feeling.

The Opiate Theory. Another theory is that, while using TENS, chemicals are released in the body that helps you feel good. These are similar to the chemicals that are released during exercise, like endorphins, that give you the good feelings that come with physical activity. Thus, the use of TENS on your body helps you feel good, and the pain that you are feeling is reduced or eliminated.

The Research Behind TENS

Many studies have been published about the use of TENS for specific diagnoses. From fibromyalgia to knee pain, if you search for a TENS study, you will most likely find one. Many studies indicate positive pain relief with the use of TENS, though others show very little positive effect with TENS.

In 2001, evidence-based practice guidelines for neck pain, low back pain, shoulder pain, and knee pain were published in the Physical Therapy Journal. These studies examined the efficacy of interventions commonly used in physical therapy for specific conditions.

In these papers, TENS received a grade of C (no benefit identified) for the treatment of low back pain, neck pain, and post-operative knee pain. There was insufficient data available to make a determination for the use of TENS for shoulder pain. For knee pain, TENS received a grade of A (beneficial) only for the treatment of knee osteoarthritis.

Is TENS Right for You?

Just because many studies on TENS show that it is probably not the most effective treatment to help you reduce or eliminate pain, you should not discount it altogether. Some people really like to use TENS, and many people find it helps to manage their pain. If you do attend PT and TENS is used, make sure it isn't the only thing used. Your PT should have you engage in an active exercise program to help your condition.

A Word From Verywell

It is important to remember that if you are attending physical therapy and TENS is used, it should not be the only treatment for your condition. Most evidence indicates that you should be actively involved in your care, and that exercise is your main tool to help treat many conditions.

The best course of action is to speak with your doctor and physical therapist to find the optimum way to manage your pain to help you return to normal activity and function as quickly as possible.

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  • Vance, Carol Gt, et al. “Using TENS for Pain Control: the State of the Evidence.” Pain Management, vol. 4, no. 3, 2014, pp. 197–209., doi:10.2217/pmt.14.13.

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