Tag Archives: tens unit


TENS Unit for Pain Relief

TENS units have been used for decades for the relief of pain. Many people use then for both acute (sudden) pains due to exercise as well as post-operative pain, or for chronic pains due to carpal tunnel, arthritis, tendonitis, sciatica, lower back pain and other pains.

TENS stands for Trans-cutaneous Electrical Nerve Stimulator. This simply means that an electrical signal is applied to the skin which stimulates nerves near the surface of the skin.

Pain Management


TENS 7000 Unit

In general, you apply the conducting pads to the skin along the area of the pain. The electrical stimulation inhibits the transmission of pain signals to the brain, preventing you from feeling pain.

When you use a TENS unit you typically have control over a number of stimulation parameters. These typically include the pulse intensity, pulse frequency, pulse duration, and pulse shape. After you apply the conducting pads to your skin you can work the controls until the pain is reduced or eliminated.

The Cochrane Collaboration published a review of TENS unit effectiveness in 2010 entitled Transcutaneous electrical nerve stimulation (TENS) for chronic pain (Review). It indicates

“TENS is generally believed to be a safe non-invasive intervention which may produce significant analgesia in many patients with moderate predictable pain associated with a range of conditions . It is used in a variety of clinical settings to treat diverse acute and chronic pain conditions, and although clinical studies of its long-term efficacy have yielded variable results, it has become popular with both patients and health professionals of different disciplines, including physiotherapists, midwives, nurses and doctors.”

A March 1997 article in The Annals of Thoracic Surgery, Control of Postoperative Pain by Transcutaneous Electrical Nerve Stimulation After Thoracic Operations, found that “TENS is useful after thoracic surgical procedures only when postoperative pain is mild to moderate; it is uneffective for severe pain.”

How Does a TENS Unit Work?

Take a look at the “Pain & Injury Doctor” providing an overview of how to use a TENS device:

In this video, I demonstrate how to operate a typical TENS unit, and strategies for placing the electrodes to achieve maximum benefit.

A TENS unit (Trans-cutaneous Electrical Nerve Stimulator) is a small device about the size of a deck of cards that can be used for managing sub acute or chronic pain. It works by “interfering” with pain signals to the brain, by flooding the pain-generating tissues with small, electrical currents that are thought to “compete” with the pain signals traveling to the brain, resulting in reduced perception of pain. It does not do anything to cure the inured site.

TENS units can be helpful by precluding the need for drugs that might be harmful to the user. It is also faster acting than ice and topical pain products.

Now, take a look at the TENS device in actual use for back pain relief:

Scientific Studies

About half the studies of TENS units for pain control have found they did not product statistically significant pain relief. One reason for this is that all the patients using the TENS device were given the same stimulation, which often was ineffective. It could not be varied until it was effective.

The best scientific studies are “double blind” studies in which neither the doctor/therapist nor the patient know the treatment the patient is receiving.

For example, the journal Pain reports on the study Efficacy of Electroacupuncture and TENS in the Rehabilitation of Chronic Low Back Pain Patients. In this study two TENS unit treatment types were used: one with a functioning battery and one with a dead battery. In both cases the intensity of the stimulation could not be felt by the patient.

When the assigned treatment was either TENS or TENS dead battery, the patients had the electrodes attached and were stimulated with a live battery. For both treatments, the intensity of stimulation was then reduced to the point that the patient could not feel the stimulation. At that point, the assigned battery (active or dead) was placed in the unit, and the unit was placed in a plastic case.

In other words, both TENS unit treatment protocols in this study used an intensity that could not be felt by the patients. So, in this study, it is not surprising that no significant difference was seen between the live battery and dead battery levels of pain relief.

Most studies are similar in that the treating levels cannot be adjusted by the patient until they produce results. This is probably why half the scientific studies are inconclusive.


TENS units are used by both professionals and by the general public to reduce the discomfort of both acute and chronic pain. They can be used in place of drugs that typically have potentially dangerous side effects.

We recommend the Tens 7000 2nd Edition with Accessories as seen in the videos on this page. It is effective and inexpensive and can be used at home whenever needed.