How to Use a TENS Unit

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TENS Unit Usage can be Confusing.

TENS therapy is one of patients' and healthcare professionals' most commonly used pain relief methods. Extensive studies and research has gone into understanding how these devices work and why they’re effective. And while more research is needed, these devices continue to be a “go-to” for those treating pain.

However, using these devices can be a tad confusing. Many factors contribute to TENS therapy’s success. This includes:

• Device settings: pulse rate, pulse width, intensity, and mode
• Pad placement
• And the use of complementary treatments.

Whether you’re still trying to decide on a device, have already purchased one, or are deciding whether TENS therapy is right for you, you’ve come to the right place.

This guide will go in-depth into everything you need to know to properly use a TENS unit. This includes the best settings for your pain, pad placement, step-by-step TENS machine instructions, and more. By reading this, you’ll not only know how to set up your TENS machine but be able to incorporate it into your rehabilitation.

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What is TENS Therapy?

Before we get into the nitty-gritty of using your device, it’s essential to understand what this treatment is and how it blocks pain.

TENS therapy is a drug-free method of pain relief. It involves using an electrotherapy machine called a TENS unit to deliver small electrical pulses to your nerves through electrodes attached to your skin. 

Pain relief is achieved in two ways:

• Pain gating: The electrical pulses activate your body’s large nerve fibers, inhibiting the small nerve fibers from sending signals to your brain. This causes you not to feel pain.
• Endorphin release: The electrical pulses activate and cause your body to release endorphins, the body’s natural pain killer. These chemicals create a morphine-like effect to relieve pain.

These devices have a significant advantage over medications (besides being non-addictive and safer) because they can target the pain directly. TENS units can treat various body parts and injuries such as:

• Back pain
• Knee pain 
• Arthritis
• Fibromyalgia
• Bursitis 
• And more.

If you’re interested in learning what conditions these devices eliminate pain from, our “TENS unit uses” article goes in-depth with studies, experts, and user feedback.

While TENS therapy does not promote healing, it does make movement easier. This is a crucial reason physical therapists and chiropractors use them on patients. Later in this guide, we’ll review the complimentary treatments that pair well with TENS therapy.

Common TENS Therapy Mistakes

By nature, TENS therapy may require trial and error to find your “TENS sweet spot.” Your sweet spot comprises the ideal device settings and pad placement to relieve pain. Below, we highlight common mistakes users make when using their device,

Placing electrodes over top of the pain, not around it.

Inexperienced users often place their electrodes over the area in pain. While this reasoning makes sense, it’s incorrect. TENS therapy relies on sending an electrical current through the nerves to block the pain. This is most effective when the pads are placed around the pain center, allowing the current to travel through the pain area.

Using only one electrode

For the current to travel through the pain requires two electrodes. Placing one electrode will not allow that current to travel. It’s also essential to always use electrodes in even numbers. Each electrode is attached to a channel, which requires two contact points to conduct a current.

Starting at too high of an intensity level (getting zapped)

The intensity level refers to the amount of electricity produced. Starting at too high of an intensity level can cause you to get “zapped.” While this is harmless, it can be uncomfortable and even painful. Be sure to start your TENS sessions at a low-intensity level and gradually increase it as needed.

Not incorporating complementary treatments

As mentioned earlier, TENS therapy does not promote healing. It only blocks pain from being felt. For best results, it’s best to add other rehabilitation methods. This includes, but is not limited to, hot & cold therapy, stretching, and exercise. The two primary purposes of TENS therapy should be to:

• Mitigate pain
• And make movement easier.

Not testing or modifying electrode placement and device settings

More often than not, users complain of a defective device after their first trial of TENS. By nature, TENS therapy requires trial and error to find the ideal settings and placement.

No pain is the same. Most devices are made with this in mind to be customizable to create a different effect. For example, acute pain requires a different pulse rate than chronic pain (which we’ll explain later).

In short, have patience. Your therapy most likely will need trial and error. But have hope. Our modes, settings, and timing section will explain how to find the proper settings for your pain.

TENS Unit Safety Precautions

As with any medical device and treatment, safety comes first. Before starting treatment, it’s vital to understand the safety measures to prevent injury. While TENS therapy is generally safe, you should take a few TENS machine precautions.

Side Effects

When first using your devices, be aware of TENS therapy side effects. These include:

• A buzzing, tingling, or prickling sensation: This is a normal effect of TENS therapy.
• Twitching muscles: When set at a higher intensity, your muscles may twitch, which is normal. However, if your TENS unit is causing muscle spasms, your intensity and settings may need adjusting.
• Skin redness or irritation from using the pads: This is another typical electrotherapy side effect. While harmless, be aware of this as it might indicate allergies to your electrodes. If redness/irritation persists, halt treatment and seek a doctor's advice.
• Nausea: Sometimes, TENS units cause nausea, specifically in younger users. This is usually temporary and goes away on its own. You may experience it with the first use, which will disappear as your body adapts. If prolonged nausea occurs, stop treatment and seek a doctor.
• Burn marks: A common question is, "can a TENS unit cause burns?" Yes, the device can burn your skin when used on sensitive skin or at higher settings. However, it is usually mild and can be remedied with burn ointment. If your burn is severe, seek a doctor.

Because TENS therapy provides a calming effect, they’re effective in allowing users to rehabilitate muscles more comfortably when stretching. 

Who Should Not Use a TENS Unit

You should avoid using a TENS device if you:

• Have a pacemaker or defibrillator
• Have a metal implant
• Have a spinal cord stimulator
• Have in-dwelling pumps or monitors

FREQUENT TOPIC

TENS Units and Pacemakers

One reoccurring TENS unit topic is the use of these devices with pacemakers. Two studies looked at this topic and concluded:

• "Patients with cardiac pacemakers should not be excluded from the use of TENS, but careful evaluation and extended cardiac monitoring should be performed." - 1990 study
• "electrical stimulation should be used with caution in patients with pacemakers and implanted cardioverter defibrillators." - 2017 systematic review

While these studies are promising, you should consult your doctor as everyone's condition differs.

Talk to your doctor if you:

• Have cancer
• Have diabetes 
• Are cognitively impaired 
• Have epilepsy
• Or are pregnant

COMMON QUESTION

"Is TENS Safe for Cancer?"

While we must preface that you should consult your doctor first, one study found promising results. They found TENS to "be beneficial in 69.7% of patients over the course of 2 months." However, more studies are needed to research its effect. Today, studies are inconclusive about the long-term impact of TENS on cancer patients.

When You Should Not Use a TENS Unit

While these devices are known for being a convenient method of pain relief anytime, anywhere, there are a few settings they should not be used. These include:

• In or around water: TENS devices emit electrical pulses which do not mix well with water. Using your device where water is present can damage you and your device.
• While sleeping: Using your device while asleep can cause wires to be tangled. It can also cause electrodes to lose attachment to your skin and “zap” you.
• While driving or using heavy machinery: TENS devices can cause your muscles to contract or twitch, which can interfere with operating moving vehicles.

Where Not to Use TENS

As mentioned prior, electrode placement is vital to TENS therapy success. This applies to TENS safety as well. Never place your electrodes on:

• Open wounds/rashes
• Swollen, red, infected, or inflamed skin 
• Cancerous lesions, or close by 
• Skin with irregular feeling 
• Any part of the head or face 
• Any part of the throat 
• Both sides of the chest or trunk simultaneously 
• Directly on your backbone (spine)

If you have pain in any of the areas mentioned above, consult your doctor for guidance.

COMMONLY ASKED

"Can You Use a TENS Unit on Your Chest?"

Yes, using your device to target pain nerves on your chest is safe. However, it's important not to place pads directly or near your heart. Pad placement should be on the other chest muscles with ample distance to your heart.

General Protective Measures

Follow these general TENS safety measures to protect yourself from injury and infection:

• Turn the device off before removing or moving electrode placement. Failure to do so can result in your device “zapping” you.
• Don’t share pads with others. Electrodes can hold germs and bacteria from your skin which can cause infection when transferred to others.
• Keep out of reach of children.
• Only use the device as instructed by your doctor or the user manual. 
• Electric devices such as EKG monitors and alarms may not work correctly while in use.

COMMON QUESTION

"Can you overuse a TENS unit?"

No, you cannot. TENS devices are highly safe to use as often and as long as needed. However, taking a 10-minute break for every hour of TENS therapy is ideal. This will give your skin a break from the materials of the pads.

TENS Therapy Modes, Settings, and Timing

TENS therapy is highly versatile and customizable, making it great for treating pain (as no pain is the same). However, finding the perfect TENS parameter to ease your pain can be confusing. This section focuses on the TENS unit protocol to simplify this process by explaining the most common modes, what each setting does and its effect, and common techniques used by healthcare professionals.

When going through your TENS unit's setup, use this section to decide which mode and settings are ideal for your pain.

TENS Modes Explained

Most TENS units come with a preset collection of modes that set the device's pulse rate and width for you. These are great for those new to TENS therapy or looking for a quick setup. The most common modes equipped in TENS devices include normal, burst, and modulation. Below, each TENS unit mode is explained in terms of its effect, the type of pain type it's ideal for, and who it's ideal for.

Normal

In normal mode, your device will send out consistent pulses which never regulate. This mode gives you complete control over the pulse rate and width.

• Pain type: Acute
• Effect: Provides a constant stimulation
• Ideal for: Those new to TENS therapy or with acute pain.

Burst

In burst mode, your TENS device sends out bursts of pulses with a break in between. The burst TENS parameters include an adjustable burst rate, adjustable pulse width, and a fixed pulse rate. This means that the device gives you options to adjust the rate of bursts and their width while setting the pulse rate for you.

• Pain type: Chronic
• Effect: Provides bursts of stimulation
• Ideal for: Those with chronic pain or experiencing pain intensity at higher than normal levels.

Modulation

In modulation mode, your device cycles between pulse width and rate to shock nerves for pain relief. Both pulse rate and width are fully customizable, and the device fluctuates each setting.

• Pain type: Acute or chronic
• Effect: Cycles between pulse width and rate settings
• Ideal for: Those with acute or chronic pain or whose nerves tend to adapt to treatments.

TENS Stimulator Settings

When using your device, you’ll have the option to customize the mode and its pulse rate, width, and intensity. Learning how to use your TENS unit's settings is essential as each has a different effect on your body. Use this in unison with your device's manual to find the best setting for your pain type (acute, chronic, and condition).

Pulse Rate (Frequency)

Your device’s pulse rate refers to how often it sends an electrical pulse to the electrodes. It’s also called “frequency” because it dictates how frequently you receive electrical stimulation.

Pulse rate is measured in hertz (Hz), or pulses per second. 35 Hz equates to 35 pulses per second, whereas 120 Hz means the device will deliver 120 pulses each second. The chart below highlights different frequency ranges and what they’re ideal for.

Caution: Higher TENS frequency settings can cause skin irritation. If skin irritation occurs, limit your treatment time.

It should also be noted that lower frequencies may be ineffective if you have an opioid tolerance.

Pulse Width (Duration)

Pulse width, also called pulse duration, is the length of the pulse your device administers. Pulse width is measured in microseconds (µs). A more extended pulse width delivers a stronger stimulation. 

When setting your pulse width, be wary of your pulse rate. Having both at a high setting may be uncomfortable. You may want each set to be opposite of the other. For example, set your device to a high frequency and a low duration or vice-versa.

When setting your pulse width, a low setting is typically better for pain relief. In contrast, a high setting will increase blood flow and contract muscles.

Modes and Settings

When selecting your mode and settings, it’s essential to be aware of the following:

• Higher pulse rates tend to cause discomfort when used in modulation or burst mode.
• Normal mode is typically okay regardless of the TENS unit frequency and width.

Intensity

Your device’s intensity level refers to the strength of the electrical pulse emitted. This setting is measured in microamperes (mA). A question commonly asked is, "how high should I set my TENS unit?" This answer varies as the ideal intensity level will depend on a few things:

• Your body’s reception of TENS therapy. Some are more or less sensitive to electrical stimulation. You may require higher intensity levels if you’ve built a resistance to opioids.
• Your level of pain. Greater pain levels require higher intensity levels.
• Your TENS device. Not all TENS units are the same, with each intensity level producing a different amount of microamperes.
• Your target body part. Certain areas of the body are more sensitive to TENS therapy.

You should always start at the lowest intensity level and gradually increase it until the pain eases. Your treatment should be comfortable. If discomfort occurs, lower the intensity level.

Be aware that muscle contractions and twitching will occur at higher levels.

Pulse Rate and Intensity

Regarding pulse rate and intensity combinations, there have been a few discoveries on their effects. The table below highlights what each combination achieves.

To summarize, a low to moderate intensity level combined with a pulse width of 80-100 Hz is ideal for fast pain relief. A high-intensity level combined with a pulse rate of 2-5 Hz will provide longer-lasting pain relief.

More immediate pain relief may be ideal if your pain level is high. In contrast, longer-lasting pain relief may be suitable to prevent sleep interruptions or for long activities such as social functions.

Timing - How Long Can You Use a TENS Unit?

Because of its high degree of safety, TENS therapy can be used as long and as often as needed.

However, it should be noted that higher settings may require frequent breaks to give your skin and muscles breaks. Failure to do so can irritate your skin and cause muscle soreness. It’s a good practice when first using your device to limit treatment to 30 minutes.

Regarding length and frequency of treatments, experts and studies have found:

• 40 minutes is the ideal time for best results.
• Chronic pain is best treated for 30 minutes while actively moving. It’s less effective while inactive (sitting still, lying down, or resting).
• Acute pain should be treated for 20-60 minutes, up to four times daily.
• Chronic pain should be treated for 20-30 minutes, up to five times weekly.

In regards to when you do your TENS therapy, consider these factors:

• When do you typically experience your pain?
• Will you be participating in activities that may cause you pain?
• If possible, can you wear your device while doing said activities?

It’s essential to be aware of these factors to make your best effort to keep your pain levels down. It can be very beneficial to start your treatment when the pain is low or non-existent. 

TENS settings and techniques

By nature, TENS therapy is a science. Each setting has a different effect on your pain. And because you can customize your TENS unit's setting's pulse width, rate, intensity, timing, and placement, there are quite a few variations you can use.

The chart below lists various TENS unit settings and techniques as their use. In the "use" column, we identify whether the TENS setting is for chronic pain or acute pain and if it has a specific effect.

TENS Unit Settings Chart

Electrode Placement

Where you place your pads is another crucial component to successful TENS pain relief. Your electrode placement dictates where the current is directed.

A few general best practices when placing electrodes include:

• It may take 3-4 tries before finding the ideal placement.
• Pads should be placed at least 1” apart.
• The closer the pads, the stronger the stimulation.
• Always wash and dry your target area before placing.
• Make sure each pad is firmly placed with no parts unadhered to your skin.
• Never place pads over bones or joints. This can cause discomfort and cause the electrodes to lose their adhesion to your skin mid-treatment.

How to Find Your Placement Area

Before placing your electrodes, you’ll want to find the area in pain first. To do so, start lightly touching your target area and note where most of the pain is. This is going to be the center of your pad placement.

Next, locate the surrounding areas with less pain. These areas will be where you’ll want to place your electrodes.

Where to Place Your Electrodes (Common Techniques)

While there are a few best practices for pad placement, there isn’t a “wrong” area to place them (aside from the areas to avoid). You may have also noticed that some techniques in the section focus on placing pads over areas such as pressure points, muscles, or simply over the pain.

Simply put, the correct placement will be dictated by if the pain is still being felt and how comfortable the treatment is.

Channel Selection and Pad Placement

Before we cover placement, it’s essential to note your device’s channels. This refers to the number of lead wires plugged in simultaneously. One channel equates to two electrodes. More channels allow you to target more or larger pain areas simultaneously.

If using more than one channel, it’s essential to be strategic with how each is placed. There are three methodologies when considering multi-channel placement:

• Cross-aligned (“X”): This method involves placing electrodes so that each channel crosses one another, creating an “x.” This placement allows the current from each channel to cross-align where most of the pain stems from.
• Parallel: With this placement, each channel is placed parallel to one another. The current from each channel does not cross. This placement method allows for a broader area of pain to be covered.
• Multiple areas/body parts: Using more than one channel is ideal if your pain is widespread or you have multiple body parts in pain. This method uses each channel on separate body parts, allowing multiple pain areas to be treated simultaneously.

Pad Placement by Body Part

Below, we’ve highlighted standard pad placement by body part. Your pad placement may vary depending on the location and cause of your pain.

Step-by-Step TENS Unit Instructions for Use

For an ideal TENS unit application, follow these steps:

• Identify the area in pain by softy touching it. Identify where most of the pain is and the surrounding area; this is where you’ll place your pads.
• Once identified, clean your skin of oil or lotion and thoroughly dry the target area.
• Remove the electrodes from their packaging and place each around the target area; ensure each pad is firmly placed and no edges are protruding (protruding edges can cause your skin to be “zapped”). Each pad should be at least 1” apart and not be touching each other or any other object.
• Connect your lead wires to each pad.
• Connect each lead wire to the device. Double check the lead wires are connected properly.
• Turn the device on at its lowest intensity level.
• Choose your desired settings.
• Turn the intensity level up until you stop feeling pain. Your muscles may start to contract.
• After the initial minutes of treatment, stimulation may weaken. This is called “accommodation” and is normal as your body gets used to TENS. Turn the intensity level up to keep the effect strong but comfortable.

If Pain is Still Felt

• Try a different setting.
• Reposition the electrodes (make sure to turn the device off first) - incorrect positioning may not allow the current to travel through the target nerves.
• Turn the intensity up.
• Check that the pads are placed firmly over your skin.
• Call your healthcare provider if you still can’t get relief.

If You Can't Feel the Current

• Check your device's power source: are the batteries appropriately inserted, dead, or weak?
• Check your electrodes: are they firmly sticking to your skin? You can attempt to reactivate their sticky surface by wetting your fingertip, gently rubbing the pad surface, and then letting it dry for one minute. If this is ineffective, new pads might be required.

If Pads Won't Stay on or in Place

• You can attempt to reactivate their sticky surface by wetting your fingertip, gently rubbing the pad surface, and then letting it dry for one minute. If this is ineffective, new pads might be required.
• Try using a skin prep wipe before placing electrodes. These remove oils and lotions to allow the pad to stick better.
• Reposition your electrodes if they’re over a joint.
• Try to sit still during treatment: Target areas closer to the joints can cause pads to unstick with movement.
• If you’re sweating during treatment, try to place medical tape over the electrodes.

Complimentary Treatments

As mentioned prior, TENS therapy does not promote healing. It only blocks the sensation of pain. For this reason, we always recommend incorporating other treatment methods into your regimen. While your TENS device does not promote healing, it can make movements much more manageable. This can make any rehabilitation, such as stretching and exercise, more manageable.

Stretching & Exercise

If you’re recovering from an injury or surgery, rehabilitation can be challenging if the pain is severe enough. This is where healthcare professionals most commonly use TENS devices.

Physical therapists will frequently use a TENS unit before, during, and even after rehabilitation sessions. These devices reduce patient pain to make movement easier, allowing for a broader range of motion. When used after exercise, they can be used to delay the onset of muscle soreness and any pain from movement.

Here are a few ways to incorporate TENS therapy with stretching and exercise:

• Before movement: Use your device at least 15 minutes before moving to allow the treatment to take effect. Locate your area of pain and set your device to your desired settings. We recommend setting your pulse rate at 80 to 100 Hz for a faster effect.
• During movement: Using your device during movement can keep the pain away throughout your regimen. Just be sure to be cautious of your TENS equipment. Your electrodes can come undone, and lead wires may pose a trip hazard. If your device has a belt clip, it might be ideal to utilize it.
• After movement: Athletes regularly use TENS units post-workout to minimize pain and treat sore muscles. One study involving 50 participants found it to reduce delayed onset muscle soreness effectively. Because your muscles tend to get sore after movements, it’s important to avoid setting your pulse to around 260µs. In this setting, it can cause muscles to contract and make the soreness worse.

Hot & Cold Therapy

Hot and cold therapy, also called contrast therapy, involves alternating hot and cold temperatures to treat an injury. Hot temperatures improve blood circulation, minimize cramping, and relieve pain. Cold temperatures minimize swelling and relieve pain. It’s important to alternate each to cancel out adverse side effects of each (heat can create more swelling, and cold can cause muscle spasms).

Using a TENS machine before or after hot and cold therapy can help relieve pain and improve blood circulation to the pain. You should never use these treatments simultaneously as moisture does not pair well with electrical currents from the machine. Removing moisture from your target area before applying electrodes is also essential.

Below, we’ve taken our step-by-step instructions for using your TENS unit with heat & cold therapy:

• Apply TENS therapy for 10-15 minutes
• Apply cold for 1 minute 
• Then switch to 3 minutes of heat 
• Again use 1 minute of cold
• Switch back to heat for 3 minutes
• Apply your cold item for 1 minute
• Heat the area for 3 minutes
• Use 1 minute of cold 
• Finish treatment with 10-15 minutes of TENS therapy.

Medications

One of the many advantages of TENS therapy is its ability to minimize (and even remove) the dependency on prescription medications. One study found TENS therapy to be an effective method of non-opioid pain relief, offering a source of pain management for patients in their emergency department.

How you incorporate TENS therapy into your pain relief regimen may vary on your condition and doctor's recommendations. One approach is to use your device before taking pain medications. After treatment, wait to see if your pain comes back, and then take your medicine. This method is excellent for using pain pills as a last resort.

Electrode Care

TENS therapy can be a very cost-effective method of pain relief. Today’s devices are very affordable and can even be covered by insurance. Your electrode storage and care are crucial to keeping your costs low. Below, we highlight a few methods of extending the lifespan of your pads.

How to Keep Your Electrodes Clean

Clean your skin before treatment.

Taking the time to clean your skin before treatment can significantly extend the life of your electrodes.

Store Your Pads in the Bag & Sheets They Came with (or invest in an electrode holder).

Your electrodes should come in a seal-tight bag and on plastic sheets. Their packaging is designed to do two things: keep moisture in and give them a clean surface to stick to. Ensure the bag is tightly shut when storing your pads to keep air from drying them out. For added convenience, you might want to consider an electrode holder. These offer an easier way to store your pads.

Wipe Your Pads Down After Each Use

Oils and hair can cause electrodes to lose their stick quicker than usual. Be sure to wipe your pads with antiseptic spray or TENS wipes after each use. This will remove any oils or hair that came into contact with your pads during treatment.

Frequently Asked Questions

Conclusion

Regarding pain relief, TENS therapy is an excellent option for those who want to block pain without using addictive drugs. These devices are portable for use anywhere and have become highly affordable. We've covered a lot in this TENS unit training.

To recap, consider these TENS unit hacks:

• Be patient with your treatment.
• Keep experimenting with different settings and pad placement to find the ideal combination.
• Always follow best safety practices.
• Incorporate other rehabilitation methods to make the most of your therapy.
• Keep track of your sessions by making notes of your device settings, pad placement, and before/after pain level. This will help you track what works.
• Be sure to clean and store your electrodes properly to extend their lifespan.
• Be aware of your pain. Know when it typically occurs or when you might be doing activities that may cause pain.

TENS therapy can quickly become a staple for any exercise or rehabilitation regimen when used correctly.

What experience have you had with your device? Have you found specific settings or placements that work best for your pain?

Leave a comment below; we'd love to know!

TENS Therapy Related Resources

About the Author

Brandon Landgraf is the Digital Marketing Manager for Carex Health Brands. He finds passion and fulfillment in creating content that enhances, improves, and enlivens others' quality of life. All of his written work is formulated to not only offer essential advice and tips but back it with proven studies and experts. His mission is to connect with readers and provide steps to make their lives better.

You can connect with him on LinkedIn here.

About Carex Health Brands

Carex is your one-stop shop for home medical equipment and for products that assist caregivers with providing the best possible support and care for their loved ones. Carex Health Brands has been the branded leader in in-home, self-care medical products for over 35 years. Our goal is to improve the lives of our customers by bring them quality products that bring dignity back to their lives. With our three nationally distributed brands, Carex Health Brands serves national, regional and independent food, drug and mass retailers along with wholesalers, distributors and medical dealers.