The term TENS is the acronym of the English words “transcutaneous electrical nerve stimulation,” which in Italian means “transcutaneous electrical nerve stimulator.” It is a device for controlling the pain that is used by placing electrodes on the skin, through which they emit fast but weak electrical impulses. It is believed that electricity blocks the nerve tracts that are used by the pain signal to reach the brain and, at the same time, induce the release of substances called “endorphins.” When they are very intense and slow, the pulsations cause involuntary muscle contractions followed by relaxation, while the faster ones can be perceived as rubbing or trembling. The effectiveness of this treatment as a painkiller is still under investigation, but some people claim to have benefited from it. It is essential to know at which points of the body the electrodes can be safely attached and when such therapy should be avoided entirely (e.g., if you have a pacemaker, a defibrillator, or a heart monitor).
Part 1: Place the electrodes in a safe manner
1. Start with the minimum settings
- Then gradually increase it to a sufficient level. Go to a physiotherapist to teach you how to switch the device – this will reduce the likelihood of using too much or too little intensity. Learn about body points that are usually massaged to relax the body. The physiotherapist has the necessary experience, can suggest to you what is best for your health and what you need to avoid.
- To find pain relief, identify the points of pain by feeling them with your fingertips and attaching the electrodes anywhere.
- The best settings vary from person to person, based on individual sensitivity level and pathology. The body can develop resistance to TENS units with only one power distribution scheme, and some models offer a random distribution.
2. Arrange the electrodes at least 2-3 cm apart
- This avoids the excessive release of electricity in a small area. Leave the device off while placing the patches. You can distribute them in different ways, depending on what’s best for your situation:
- Around the painful area or over the acupressure points, the physiotherapist showed you on a table.
- If the device has black and red electrodes, place the black ones in places far from the trunk, for example, on the arms or legs, while the red ones must stay close to the box. In this way, you can prevent unpleasant electrical impulses from reaching the central nervous system – this arrangement also stimulates muscle contraction.
- You can place them online in the form of “X” or squares, but must always be at least 2-3 inches apart. To decide an “X,” place one pair of electrodes (one positive and the other negative) diagonally and the other pair on the vertical diagonal.
3. Change the amount of electricity slowly, gradually and carefully
- Start with the device turned off and turned it on when the display shows the minimum setting.
- Gradually increase the intensity of the electrical current until you feel a pleasant tingling sensation – if you are in pain, the level is excessive.
- Remember that such an intense current is not necessarily more effective – if you overdo it, you will not get more pain relief.
- The body could get used to a certain amount of electricity over time – if that happens, increase the intensity slightly and slowly.
4. Remember which setting is right for you
- Once you have identified the amount of power and the location of the electrodes that you are using, continue to use them.
- This does not mean that you need to start each session at this level because you may feel pain – begin at a lower intensity and then gradually increase it to your preferred level.
- You can use a TENS device as long as you like if you opt for more prolonged use, eg. For example, during other activities, you can attach it to your belt with a clip or store it in your pocket.
- The duration of each session depends on the pathology to be treated, its chronicity, and the body’s response – the physiotherapist will give you all the information and the correct frequency of use.
- Be aware that if you surrender to TENS too often, your body will “get used to” electrical impulses and, over time, will lose the positive effects.
5. Make sure the electrodes are covered with enough gel or water
- Keep in mind that not only does the body react to specific device settings, but the therapeutic experience can vary depending on the amount of lubricant. A good dose of gel or water allows for better impulse conduction.
Part 2: What to avoid
1. Do not place the electrodes in dangerous areas of the body
- Eyes and ears;
- Front or side of the neck, near the main arteries;
- Spine (but you can place the electrodes across the sides of the range);
- The left side of the chest, near the heart;
- Do not place an electrode on the chest and one on the back;
- varicose veins;
- Damaged skin or new scars heal;
- Areas with low tactile sensitivity.
2. Avoid TENS in any part of the body if you have a condition that makes this therapy dangerous
- Some health conditions are incompatible with the procedure, which may even pose a serious threat.
- If you have a pacemaker or other electrical device implanted in your body, TENS electrical pulses may interfere with the signal and prevent the instrument from functioning.
- If you have epilepsy, you may be more sensitive to electricity and should not use this type of analgesic.
- If you have disorders that alter the rhythm or heart rate, the heart could be extremely sensitive to electricity and change its functionality;
- If you are allergic to the material of the electrode patch, you should choose allergic models;
- If you are pregnant or think you are pregnant, do not use a TENS device without being prescribed by your doctor. The risks of this therapy during pregnancy are not known, so do not undergo the consent of the gynecologist – some women believe it is useful to manage the suffering of the job, but you must ask the doctor if it is a safe solution for you and the child is;
- If you have any doubt, contact your doctor.
3. Do not use TENS for certain activities
- In some cases, it can prove to be riskier.
- If you are in the bath, shower, or pool, remember that the water changes the way and the areas where you carry electricity;
- Do not take TENS while you sleep;
- When driving a motor vehicle, the sensation caused by electrical impulses can distract you;
- When using a machine, do not use the device to avoid sudden interactions.
- The electrical impulses of a TENS device should not cause problems for airlines, but you should always ask for permission before you use it during a flight.
part 3: Realistic expectations
1. Reduce the possible disappointment if you know what to expect
- This type of therapy generally has no immediate effect, so you need to be patient.
- Some people say that it takes 40 minutes before the pain is reduced.
- Most patients only benefit during therapy – as soon as the device is switched off, the pain recurs.
- If the therapy is ineffective, it is essential to make an appointment with the physiotherapist to learn how to change the settings – this will help you find the most useful ones for your health conditions.
2. Know for which problems TENS is more effective
- Menstrual cramps;
- Sports injuries;
3. Maximize the benefits by combining other pain management techniques
- Both prescription and over-the-counter medications;
- Physical Exercise: Ask your doctor what type of physical activity is appropriate to your state of health;
- Relaxation techniques: Depending on the cause of the ailment, you can use TENS during meditation sessions, deep breathing, yoga, or to visualize soothing images.
- When using a TENS device, always follow the manufacturer’s instructions.
- If you are not sure if this therapy is safe for you, ask your doctor for confirmation.
- As indicated above, do not apply electrodes to the head, eyes, ears, tongue, jugular veins, and arteries- do not place them in a line along the spine and neither along the blood vessels.
- Do not use a TENS device if you have a pacemaker, cardiac monitor, or implanted defibrillator.
The benefits of transcutaneous neurostimulation
Although transcutaneous neurostimulation is widely used in hospitals and physiotherapy clinics, irrefutable evidence of its effectiveness is relatively weak. It isn’t easy to design a randomized clinical trial protocol with a placebo to evaluate it. Subjects may have electrodes attached to the skin; they can hardly ignore that the electric current passes or does not pass.
We also know that the placebo effect is relatively significant in the perception of pain, which can easily skew the results of clinical trials. As a result, despite abundant scientific literature, only a few applications (knee osteoarthritis and anesthesia in dentistry) are well documented. This explains why the effectiveness of transcutaneous neurostimulation remains controversial.
Here is the presentation of the benefits of this technique given the scientific literature:
Relieve the symptoms of osteoarthritis of the knee
Numerous clinical studies have evaluated the potential effects of transcutaneous neurostimulation in patients with osteoarthritis of the knee. In general, the results indicate a decrease in joint stiffness and pain associated with osteoarthritis. However, there has been little improvement in the functional capacity of patients.
Perform an anesthetic action in dentistry or dental surgery
Since the 1990s, studies have shown that the use of TENS during dental procedures can reduce the discomfort associated with anesthetic injections, reduce pain during the process, and reduce medication use.
Improve memory disorders in patients with Alzheimer’s disease
Clinical studies have concluded that transcutaneous neurostimulation may improve some symptoms in patients with Alzheimer’s disease, mainly regarding memory and mood. A placebo study found significant improvement in cognitive function and short-term memory in patients with Alzheimer’s disease after four weeks of TENS. However, after six months, no difference was more observable between the two groups.
Relieve the pain associated with dysmenorrhea
In 2002, one evaluated the effectiveness of TENS in relieving pain caused by dysmenorrhea. The results were contradictory. In 2007, two small studies found that transcutaneous neurostimulation could act in the short term on the pain experienced during menstruation.
Relieving pain during childbirth
In a 2007 study, women in both groups (TENS and TENS placebo) were stimulated on two specific points of acupuncture. Women receiving true transcutaneous neurostimulation felt less pain in the first phase of labor than those in the placebo group. The authors conclude that this may be a useful complementary therapy.
Relieving chronic low back pain
The effects of transcutaneous neurostimulation or electroacupuncture to treat chronic low back pain have been the subject of several controlled clinical studies to date, and the results remain controversial. The experts concluded that TENS could be used as an immediate additional treatment to reduce pain in the short term. However, they would not have had a positive effect on long-term pain reduction.
Also, other research has shown that electroacupuncture can reduce the pain of individuals with rheumatoid arthritis of the hand, relieve migraines or relieve pain related to various chronic pain (osteoarthritis). Pancreatitis, myofascial syndrome, diabetic neuropathy, low back pain).