A TENS unit, or transcutaneous electrical nerve stimulation device, is used primarily to reduce pain signals from nerve endings.  It does this by using “small electrical impulses through electrodes that have adhesive pads to attach them to a person’s skin.”¹  This use of electricity works to reduce pain by flooding the nervous system and reducing its ability to transmit pain signals to the spinal cord and brain.  This has become especially popular for those suffering with chronic lower back pain.  Many TENS units are portable and battery operated, and using them can help tremendously.  Therapists also use TENS units (and similar devices) in preparation to perform chiropractic adjustments.  The therapy helps muscles relax and the patient experience less pain during physical therapy.²

An E-Stim device, or electronic muscle stimulator, is used to promote muscle growth and athletic training. Physical therapists and chiropractors will often use an EMS unit for rehabilitating muscles.  The current used in EMS units mimics the same brain signal that causes a muscle to contract.  Some may use EMS units to recover after a hard workout, and many use them to help maintain muscle strength due to atrophy or injury.

Does it Hurt?

TENS and EMS units should never hurt per se, although the sensation may be uncomfortable.  Your therapist will often start your therapy at a low setting and increase the current until you are at the threshold between comfort and pain.  After a few minutes your body will have adapted to the sensation and the therapist will increase the current even more.  This applies to both TENS and EMS units.

What Does It Feel Like?

Both therapies feel like tiny electric shocks, although it is not necessarily painful.  Many people report that as soon as the TENS unit begins their pain is lessened.  EMS units often are surprising in their sensations that many people instantly understand how it is helping them as they watch their muscles contract and relax.

What If I Cannot Use TENS or EMS due to a health condition?

All therapy should first and foremost be approved by your primary care physician, and sometimes TENS or EMS therapy is not appropriate for everyone.  Pregnant women, people living with a pacemaker, or those with epilepsy should not use these therapies.  If your doctor advises against TENS or EMS therapy there are still plenty of approaches to help you get the most out of your physical therapy, such as heat therapy or deep tissue massage.  Natural Health Sports Therapy is able and prepared to offer you the best of TENS, EMS, and adjunct therapy to help you feel your best.


  1. Medical News Today 
  2. Article: Are TENS and EMS units the same thing?