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12-month warranty
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TENS Units & Muscle Stimulators – Differences and Safety Guidelines

A small wing iTENS electrode and refill gel pads

Transcutaneous Electrical Nerve Stimulation (TENS) machines are primarily used as a method of pain relief. Meanwhile, Electrical Muscle Stimulation (EMS) machines help retrain the muscles and improve muscle strength. TENS units & muscle stimulators both help people during rehabilitation, albeit in different ways. Knowing the differences is crucial to effectively and safely using either machine. Furthermore, individuals should consult health professionals before using any electrotherapy device to ensure safety. Professionals may advise them if they are suited for electrotherapy.

TENS and EMS units are available for convenient home use. People may purchase them without medical prescriptions from online stores or pharmacies. They use TENS for pain management. Meanwhile, athletes use EMS for training. However, people must take care to avoid excessive use of these machines because they may cause adverse effects like skin irritation and nerve damage. This topic will present the differences in functions, device features, and safety guidelines of TENS and EMS devices.

TENS Units & Muscle Stimulators – Difference in Functions

TENS units & muscle stimulators are both electrotherapy devices that help people during rehabilitation. Both use externally applied electrodes to deliver electrical currents to the skin. However, their purposes are different, and knowing their differences is crucial. This allows the user to maximise the effects of each device.

A TENS machine uses electric stimulation to provide temporary relief from pain. High-frequency stimulation triggers spinal nerve cells to block pain signals from reaching the brain. Meanwhile, low-frequency stimulation induces the release of endorphins. These are natural painkillers that relieve the ache in the targeted area. Its settings are adjusted to low or high frequencies to address chronic or acute pain.

On the other hand, EMS machines help improve muscle strength and reduce muscle atrophy. They help speed up the recovery process, but it does not relieve pain. Stimulation for EMS devices causes involuntary muscle contractions and helps reach areas that exercise may not. It is helpful for patients suffering from post-stroke complications and paralysis. Furthermore, some athletes use them during their warm-up exercises.

Benefits of Electrotherapy

There are several benefits to using TENS and EMS machines. Here are some of them:

  • TENS machines are alternative pain management methods that are convenient for many.
  • TENS therapy may reduce or replace the intake of pain medication. This allows people to avoid allergic reactions and adverse effects of pain medicines.
  • Electrotherapy does not have addictive effects.
  • Electrical stimulation can have a massage-like effect, which relaxes the muscles and increases blood flow.
  • Endorphins from low-frequency stimulation can reduce inflammation and improve moods.
  • EMS machines may help with athletic training and muscle tone.
  • Electrotherapy may help reduce spasms during cramps.

A woman wearing four iTENS electrodes on her leg and foot

TENS Units & Muscle Stimulators – Device Features

Doctors and physical therapists use TENS units & muscle stimulators in their treatment plans. Nowadays, people also use TENS and EMS machines in their homes. They purchase these machines online or in pharmacies for convenient use. This allows them to avoid the time costs of going to hospitals and pain clinics.

Generally, TENS machines have a frequency range of 1-150 Hz and an intensity range of 0-80 mAmp. Meanwhile, EMS machines offer more power. They have a frequency range of 25-400 Hz and an intensity range of 1-120 mAmp. Both devices have adjustable settings to produce specific effects. Moreover, TENS machines offer pre-set modes to address some acute and chronic pain conditions.

Furthermore, TENS and EMS are both battery-operated devices. Some devices use lead cables to deliver the electrical currents, while some use Bluetooth controllers and pads to control the electrical impulses. Additionally, both devices have compact designs for convenient use in various settings. Lastly, EMS and TENS have adhesive electrodes in different shapes and sizes.

How Electrotherapy Works

Electrotherapy devices like TENS and EMS use electrodes to deliver electrical currents to the skin. These pads are placed on different body parts depending on the condition. TENS machine electrode pads are placed near or on the origin of the pain. This allows the stimulation to relieve the pain using endorphins or block pain sensations using the spinal nerve fibres.

Meanwhile, EMS machine electrodes are applied to key muscle groups. This allows the electric currents to penetrate the muscle fibres and induce contractions. This can stimulate the muscles or teach them how to contract and relax. This improves muscle function and muscle tone.

The iTENS smartphone app

TENS Units & Muscle Stimulators – Safety Considerations

Individuals should consult medical professionals before using TENS units & muscle stimulators. This allows them to get advice regarding duration, regularity, and settings they may use during the session. Additionally, users should read the guidelines provided by their device manufacturer. This will help them understand how to use their machine.

Moreover, there are health conditions that negatively react to electrical currents. This includes those with a history of cancer, epilepsy, seizures, and heart disease. Those with electrical and metal implants should also avoid using TENS. This is because electric currents may cause them to malfunction. In addition, pregnant women should abstain from using TENS before labour.

Furthermore, proper pad placement is crucial to the safe use of the machine. Avoid sensitive areas like the mouth, eyes, throat, spine, and chest. People should also avoid placing adhesives on irritated, damaged, or broken skin. In addition, they must not sleep, drive, or operate heavy machinery during an electrotherapy session. Lastly, they should not use these devices while submerged in water.

Potential Side Effects

Overuse of electrotherapy devices may cause adverse effects. Thus, it is crucial to follow the guidelines for using these machines. Individuals must also stay aware to prevent things from going awry. High-frequency stimulation may cause redness, skin irritation, and blisters if the person exceeds the prescribed duration time. Moreover, they may build tolerance to the electric currents over time.

Prolonged use of EMS may also overtrain the muscle and cause additional fatigue. It may also cause sensitivity and nausea. In some cases, excessive use of EMS machines may cause muscle and nerve damage. It is crucial to seek medical attention if this occurs.


TENS units & muscle stimulators help many people during rehabilitation and daily life. TENS machines induce the body processes that relieve acute and chronic pain. Meanwhile, EMS machines induce involuntary muscle contractions to strengthen them. However, some individuals should avoid using electrotherapy devices because it may cause their conditions to worsen. This is why consulting a healthcare professional before using TENS or EMS machines is crucial.

Moreover, people should follow the guidelines to avoid the adverse effects of overusing electrotherapy devices. It is also vital to get reliable devices that suit their needs. FDA-cleared devices undergo rigorous testing to ensure the device is safe to use. There are many options for machines available in the market. One option for a wireless TENS machine is the iTENS from iTENS Australia. It has rechargeable batteries and uses innovative wing-shaped electrodes for convenient pain relief.

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