Medical tens units have many uses, depending on the type of pain a patient is experiencing. Some units come with the ability to perform ultrasounds, too, making them even more useful. Look for a unit that offers you different types of stimulation. These units can administer either high or low frequencies, based on what the patient's needs are.

High Frequency versus Low Frequency

High frequency current is generally effective when it comes to treating acute pain or pain that appears to be short-term. By contrast, low frequency current, which operates by stimulating endorphin release, is useful for long-term or chronic pain conditions. High frequency current tends to take effect somewhat more slowly than low frequency; however, the pain relief appears to be more durable and easy to sustain. By contrast, low frequency pulses are sometimes more difficult to tolerate, but produce more immediate effects.

When looking for a vendor of tens units, try to find one that offers a wide variety to choose from. Some vendors offer pocket-sized, fully portable tens machines. These machines are about the size of a deck of playing cards--the portability factor can't be beat. They are ideal for traveling practitioners as well as for patient home use. The smaller units should come with a belt clip or other carrying device.

Most patients feel positive results in approximately 30 minutes. When you're using high frequency current on a patient, there's no set limit for treatment. Sometimes, a session of 60 minutes will provide pain relief for the rest of the day (or at least a good several hours). Patients with more severe conditions may need to use a tens machine for several hours a day (or all day, in very severe cases).

Medical tens units are proven effective for the relief of pain, and are a great alternative to addictive painkillers or other drugs. These units are safe, non-invasive, and FDA-regulated. They are only available by or on the order of a physician, as mandated by federal law.