TENS for Pain Relief: The Science Behind Transcutaneous Electrical Nerve Stimulation

TENS therapy: an alternative for pain relief

What is transcutaneous electrical nerve stimulation (TENS)?

Transcutaneous electrical nerve stimulation (TENS) is a non-invasive method of pain relief. In this form of therapy, electrical impulses are conducted through the skin to the nerves. These impulses help to suppress pain signals and to promote the release of the body’s own endorphins, its natural painkillers.

TENS devices generally consist of a small, portable stimulator and electrode pads that are applied to the skin. These pads are placed strategically around the painful area in order to achieve the greatest effect.

How TENS therapy works

TENS therapy works by delivering electrical impulses that stimulate particular nerves. This stimulation can block or reduce the pain signals sent through the spinal cord and the brain. As a result, the patient can experience noticeable pain relief.

• Blocking of pain signals: electrical impulses block the transmission of pain signals to the brain.
• Release of endorphins: the stimulation promotes the release of endorphins, which are natural painkillers.
• Improved circulation: the muscle contractions triggered by the electrical impulses can improve circulation and support healing processes.

In addition to relieving pain, TENS therapy can also help to relax the muscles and release muscular tension. It is used for a variety of types of pain, including chronic and acute pain as well as muscular tension. You will find further information on where TENS is used in our section on the applications of TENS.

Because it is easy to use and non-invasive, TENS therapy offers an attractive alternative to drug-based pain management. It is important, however, to choose the right electrode placement and settings in order to achieve the best possible results. You will find guidance on using TENS devices correctly at home in our section on how to use TENS correctly at home.

Applications of TENS

Chronic pain

Transcutaneous electrical nerve stimulation (TENS) is particularly effective in the treatment of chronic pain. Chronic pain can have a range of causes, such as shoulder osteoarthritis, an artificial shoulder joint or tendon reconstruction. TENS can help to ease this pain and make everyday life easier for patients.

• Back pain: frequency high; effectiveness of TENS 70 to 80 per cent
• Joint pain: frequency medium; effectiveness of TENS 60 to 75 per cent
• Nerve pain: frequency low; effectiveness of TENS 50 to 65 per cent

Acute pain

TENS therapy is also frequently used for acute pain. Acute pain can be caused by injuries such as sports injuries, bone fractures or a collarbone fracture. Applying TENS can reduce pain quickly and effectively.

• Injuries: frequency high; effectiveness of TENS 80 to 85 per cent
• Operations: frequency medium; effectiveness of TENS 75 to 80 per cent
• Acute inflammation: frequency low; effectiveness of TENS 65 to 70 per cent

Muscular tension

Muscular tension is another common application for TENS therapy. It can have various causes, such as calcific shoulder or procedures for early-stage and advanced osteoarthritis. TENS can relax the muscles and relieve pain.

• Neck muscles: frequency of tension high; effectiveness of TENS 75 to 80 per cent
• Back muscles: frequency of tension medium; effectiveness of TENS 70 to 75 per cent
• Shoulder muscles: frequency of tension low; effectiveness of TENS 65 to 70 per cent

These varied applications show TENS therapy to be a valuable addition to conventional pain management. It is important to choose the right electrode placement and suitable settings in order to achieve optimal results. You will find further information on correct use in our guidance on shoulder arthroscopy and tendon reconstruction.

The scientific basis

How TENS relieves pain

Transcutaneous electrical nerve stimulation (TENS) is used to relieve pain by means of electrical impulses. These impulses are transmitted to the nerves through electrodes on the skin. The mechanism of pain relief through TENS is based on several theories:

• Gate control theory: this theory holds that the electrical impulses close the gate that conducts pain signals to the brain. The pain stimuli are thereby blocked and less pain is perceived.
• Release of endorphins: TENS can stimulate the production of endorphins, the body’s own painkillers. These endorphins bind to receptors in the brain and reduce the sensation of pain.
• Change in pain perception: electrical impulses can alter the perception of pain by stimulating the nerves and so distracting from the actual pain signals.

Studies and research findings

A number of studies have examined the effectiveness of TENS therapy in treating pain. Research has shown that TENS can be effective for various types of pain, including chronic and acute pain.

• Study A, 2018, 120 participants: 70 per cent of participants reported significant pain relief.
• Study B, 2020, 85 participants: 65 per cent reduction in pain intensity in chronic pain.
• Study C, 2019, 150 participants: TENS produced rapid pain relief in acute injuries.

Some important research findings include:

• Chronic pain: a study from 2018 with 120 participants found that 70 per cent of patients experienced significant pain relief. You will find more information on chronic pain in our areas of expertise section.
• Acute pain: research findings from a study conducted in 2020 showed that TENS produced a 65 per cent reduction in pain intensity in patients with acute pain.
• Muscular tension: a further study from 2019, involving 150 participants, reported rapid relief of muscle pain and tension.

These studies support the effectiveness of TENS therapy in relieving pain and provide a scientific basis for its use. However, a doctor should be consulted before use in order to discuss possible risks and contraindications. You will find further information on various pain conditions and their treatment under osteoarthritis therapy and tendon therapy.

Benefits and risks of TENS therapy

Benefits of TENS for pain relief

Transcutaneous electrical nerve stimulation (TENS) offers numerous benefits for relieving pain effectively. The most important benefits include:

• Non-invasive method: TENS is a non-invasive form of treatment that requires no surgery.
• Reduced use of medication: by using TENS, patients may be able to reduce their pain medication, which lowers the risk of side effects and dependence.
• Versatility: TENS can be used for a wide range of pain, including chronic and acute pain as well as muscular tension.
• Ease of use: the devices are generally user-friendly and can be used at home. You will find detailed guidance on correct use in our article on how to use TENS correctly at home.
• Individually adjustable: TENS devices offer various settings for intensity and frequency, so the therapy can be tailored to the individual.
• Rapid relief: many patients report rapid relief of their pain after using TENS.

• Non-invasive method: no surgery required
• Reduced use of medication: lower risk of side effects and dependence
• Versatility: usable for various types of pain
• Ease of use: simple to use at home
• Individually adjustable: various settings for personalised therapy
• Rapid relief: quick pain relief after use

Risks and contraindications when using TENS

Despite the many benefits, there are also some risks and contraindications that must be taken into account when using TENS:

• Skin irritation: some patients may develop skin irritation or allergies in response to the electrode pads.
• Not suitable for everyone: TENS is not suitable for patients with certain health conditions, such as a pacemaker, cardiac arrhythmia or epilepsy.
• Pregnancy: pregnant women should use TENS only after consulting their doctor.
• Areas with reduced sensation: using TENS on areas of the body with reduced sensation can carry risks.
• Improper use: improper use of TENS devices can lead to injury or a worsening of symptoms.

• Skin irritation: allergic reactions or skin irritation caused by the electrode pads
• Not suitable for everyone: contraindicated in patients with pacemakers, cardiac arrhythmia or epilepsy
• Pregnancy: use only after consulting a doctor
• Reduced sensation: risk when applied to areas with limited sensation
• Improper use: possibility of injury or worsening of symptoms

Patients with specific health problems such as elbow surgery or a collarbone fracture should always consult a specialist before using TENS. You will also find further information in our articles on sports medicine consultation and shoulder osteoarthritis.

TENS devices and their use

In transcutaneous electrical nerve stimulation (TENS), choosing the right device plays a decisive role in how effective the therapy is. Different types of TENS device offer different benefits and applications. It is also important to know how to use these devices correctly at home.

Types of TENS device

There are various types of TENS device, which differ in their functions and areas of use. The most important types are:

• Conventional TENS devices: these devices are widely used and provide straightforward pain therapy through continuous electrical impulses. They are well suited to treating chronic and acute pain.
• Acupuncture TENS: these devices imitate the stimulation of acupuncture points and are particularly effective for muscular tension and certain types of chronic pain.
• Burst TENS: burst TENS devices deliver impulses in short, intense bursts and are ideal for relieving pain from severe muscular tension.
• Modulated TENS: these devices vary the frequency and intensity of the impulses in order to reduce the body’s habituation effect. They are particularly suitable for long-term pain management.

How to use TENS correctly at home

Using a TENS device correctly at home involves a few basic steps. Following them will achieve the best possible pain relief while minimising the risk of side effects:

• Electrode placement:
  • Placement of the electrodes is crucial. They should always be applied to clean, dry skin.
  • The electrodes should be placed close to the painful area, but not directly on an open wound or inflamed skin.
  • For specific pain points, particular placements may be more appropriate. Learn more about electrode placement for different types of pain.
• Setting the intensity and frequency:
  • Start with a low intensity and increase it gradually until a pleasant tingling or vibrating sensation is felt.
  • Different frequencies can have different effects. A lower frequency (2 to 10 Hz) is often better suited to relieving chronic pain, while higher frequencies (80 to 120 Hz) are more effective for acute pain.
• Regularity and duration of use:
  • A typical TENS session lasts about 20 to 30 minutes and can be repeated several times a day.
  • It is important to use the device regularly in order to achieve the best results. Daily use over a longer period can increase its effectiveness.

Safety information

There are some important safety points to observe when using TENS devices:

• Use the device only after consulting a doctor, particularly if you have an electronic implant such as a pacemaker.
• Remove the electrodes immediately if severe pain, skin irritation or burns occur.
• Keep the devices and electrodes away from children and store them safely.

Further information

For more detailed instructions and further information on TENS therapy, please visit our other articles:

• Shoulder pain
• Treatment options for chronic pain
• Additional treatments for joint pain

Tips for effective TENS therapy

Choosing the electrode placement

For transcutaneous electrical nerve stimulation (TENS) to work at its best, correct placement of the electrodes is decisive. You should always place the electrodes close to the source of the pain in order to achieve the best results. Placements may vary, however, depending on the type of pain.

• Back pain: on both sides along the spine
• Knee pain: above and below the kneecap
• Shoulder pain: around the painful shoulder (see also shoulder pain)
• Elbow pain: both sides of the elbow (see also elbow surgery)

You will find further information on choosing the electrode placement in our article on calcific shoulder.

Setting the intensity and frequency

Setting the intensity and frequency of the TENS device plays a central role in effective pain relief. The intensity should be high enough to have a noticeable effect, but not so high that it becomes uncomfortable. The frequency can vary according to the type of pain and personal preference.

• Low (0 to 5 mA): slight or no sensation
• Medium (6 to 15 mA): clear but comfortable sensation
• High (16 to 30 mA): strong but tolerable sensation

• Low frequency (1 to 20 Hz): chronic pain
• Medium (21 to 70 Hz): acute pain
• High frequency (71 to 150 Hz): muscular tension (see also muscular tension)

Regularity and duration of use

For effective TENS therapy, the regularity of use is just as important as the duration of each session. Continuous use leads to better results than sporadic use in most cases.

• 20 to 30 minutes: one to three times a day
• 40 to 60 minutes: one to two times a day

To achieve maximum results, it is advisable to review and adjust your use regularly. For specific methods of treating shoulder pain, read our article on shoulder osteoarthritis.

By keeping these tips in mind, patients can get the most out of TENS therapy and achieve effective pain relief. You will find additional information and guidance on correct use under how to use TENS correctly at home.