Chronic-pain patients, physical-therapy clinics and injured athletes use TENS machines to improve pain symptoms. A TENS (transcutaneous electrical nerve stimulation) unit sends small amounts of electricity through you to interrupt pain signals and create more pain-relieving chemicals, according to the Healthcare Information Directory. You can wear it almost anywhere and use it throughout the day. Some units have multiple adjustable settings, while others only have one or two, so it's important to learn how to operate your machine. Study your machine's instructions as well as the machine itself before you use it.
Read the instructions manual for your unit. Read through all safety precautions and setting instructions to learn how to use your machine completely. Pregnant women, people with pacemakers and patients with seizure disorders and heart disease should avoid these machines unless a doctor recommended their use. The placement of the pads is also critical. They should not be placed on the front of the neck, over the heart or on a known tumour.
Understand what pulse width does. The pulse width (duration) is how short or long the actual electrical pulse will transmit. This can be between 40 and 250 microseconds. Generally, higher pulse-width settings are used for shorter periods of time, and lower width settings can be tolerated longer.
Know what pulse frequency does. The pulse frequency or rate is how often the electrical impulse will be transmitted during a certain period of time. This can be between 1 and 250 hertz. Determine whether you can adjust this on your unit.
Know the difference between machine modes. The two modes on the machine are continuous or burst. The modes are either on or off. Continuous is constant. An electrical burst is introduced at predetermined intervals in burst mode, which is effective for stimulating nerve impulses and maximising the endorphin-like effect (natural pain-free feeling).
Use a high-TENS or a rapid pulse rate for pain relief. This is ideal for back or knee pain that is constant. Set the current at a level you can tolerate without adverse reactions such as jerking or discomfort. Start by going to a higher level and turning it back down to your comfort. Put the pulse width at 100 microseconds. Set the frequency between 90 and 130 hertz (Hz). If these adjustments are not possible on your machine, find the program that closely matches these on your unit.
Use a low-TENS or slow pulse rate for analgesic effect over time. This is suited for stimulation of your body's own healing and produces an acupuncture-like effect. Set the current level at a comfortable range for you. Put the pulse rate (width) at 200 to 250 microseconds. Put the pulse frequency at 2 to 5 cycles Hz. If you cannot adjust these settings, find out which program is closely matched on your unit.
Experiment with adjusting pulse width and frequency and duration of time used for maximum benefit. Do not assume that your pain will respond the same way as someone else's with a TENS unit.
If the TENS unit makes symptoms worse, discontinue use and check with your medical professional. Do not use the unit while driving. The pads can cause skin sensitivities or allergic reactions for some people.