The Pain Gate Control Theory

Man with back pain leaning against a wall

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Scientists have many different theories about pain and the best ways to get control of your pain. One popular idea is called the pain gate control theory.

The pain gate control theory states that "gates" allow certain stimuli to pass through neural pathways to your brain. Non-noxious stimuli, the ones that don't make you feel pain, pass through the "pain gate" and then help close the gate so painful stimuli cannot reach your brain.

Therefore, you may be able to decrease or eliminate pain that you are feeling by allowing only "safe" and non-noxious stimuli through the gate to your brain.

Understanding the Anatomy of Pain

Let's keep the anatomy of pain simple. Specialized nerve endings travel from your body to your spinal cord and, ultimately, into your brain. These nerves serve as pathways where stimuli travel.

Stub your toe, and an impulse is generated that quickly moves from your toe to your brain. Your brain then interprets what has happened to your poor toe.

Based on your current location (in the shower) and your previous experiences there (you've stubbed your toe on that silly door jamb before), your brain knows what happened and the noxious stimulus that occurred as a result of banging your toe is felt as pain.

The Purpose That Pain Serves

When something that may harm your body, like a hot stove or a sharp knife, comes in contact with specialized nerves, pain may be felt. This alarm tells your brain that something dangerous may be happening to your body and that prompt attention should be given to the painful stimulus to protect your body against the problem.

You can think of pain as your body's alarm system.

But pain can be tricky, because pain may be sensed by your brain when there is no actual emergency or potential harm to your body. The sensation of pain is complex, and other factors besides nerves sending signals to your brain may be at play.

Other psychological variables that may affect the way you feel pain may include:

  • Your previous experiences
  • Your expectations and beliefs about pain
  • Anxiety
  • Depression
  • Your current environment and surroundings

These psychological factors, along with actual noxious stimuli from your body to your brain, shape how you feel pain and how your body reacts to it. Thus, the feeling of pain in your body is multi-factorial: it occurs as a result of all of your past experiences and future expectations mashing into each other in your complex brain.

Some people with significant injuries fail to feel pain. Imagine a soldier on a battlefield. They are under intense enemy fire, and a bullet grazes their arm. They may report very little pain felt at that time since the main goal at that particular point in time is merely getting to safety. Therefore, the soldier's brain may not pay much attention to the wound caused by the bullet until they are out of harm's way on the battlefield.

Other people with very little or no tissue damage experience intense pain. Perhaps someone develops low back pain that is constant in nature and limits the person's ability to move properly. Diagnostic studies like X-rays or MRIs may show no tissue damage or injury, yet the person still experiences intense and debilitating pain.

Thus, our body's alarm system is imperfect. The presence or absence of pain does not always give an accurate representation of the status of the body's tissues.

Controlling Pain with the Gate Theory

Imagine a pathway of nerves that travel from your body to your brain. These nerves communicate information to your brain about pressure, sensations of heat or cold, and pain.

When these nerves are stimulated, they travel to your brain and your brain interprets the stimulus. It may be pain, soft touch, tingling, pressure, heat, or cold.

What if there was a gate in this pathway, and the gate only allowed certain messages to pass through the pathway at certain times? What if you could apply a stimulus to the body, like a mild electrical tingling sensation, that would pass through the gate and not allow other messages through to your brain?

That is how the pain gate theory works: Apply a non-noxious stimulus to your body that closes the gate and does not allow the painful stimulus to enter your brain.

Transcutaneous Electrical Nerve Stimulation (TENS)

There are certain stimuli used to create non-noxious signals to close the gate. The most popular of these is called transcutaneous electrical nerve stimulation, or TENS. It is often used by healthcare professionals to help patients get control of their pain, and it uses the gate theory to accomplish this task.

To use TENS, small electrodes are applied to your body. These electrodes are attached to a TENS unit via a small wire, and an electrical impulse is then applied to the electrodes.

This impulse is usually felt as a slight tingling sensation. Sometimes, the electricity makes your muscles in the area of the electrodes gently contract and relax.

The tingling sensations of the TENS pass through the gate and are experienced as a pleasant feeling. When this happens, the "gate" in the neural pathway closes, and painful stimuli are prevented from reaching the brain and being felt.

Other Stimuli

Some people with chronic pain benefit from having an electrical stimulation wire implanted along their spinal canal. This wire stimulates the nerve fibers directly, helping to decrease pain and improve the overall quality of life.

Even something as simple as rubbing your injured body part can be used. When you stub your toe and feel pain there, you may rub it to help it feel better. It is theorized that the rubbing stimulus goes through the gate and closes it to the painful stimulus.

Pain Science and Research

The pain gate control theory is just that—a theory. And theories need to be tested and challenged with science. Since the feeling of pain is so subjective, testing it can be a challenge.

Some researchers have put the pain gate theory to the test be using electricity to stimulate various types of nerve fibers. It has been shown that specific types of stimuli do excite pain nerve fibers while other types of stimuli inhibit these fibers. This leads researchers to conclude that a gate mechanism is at work.

Other research has found that while the gate theory may help control some pain, a more global bio-psycho-social model of pain sensation is more accurate. This takes into account the many factors that may make you experience pain including your anatomy, psychological experiences, and your interactions in society.

The studies surrounding the use of TENS show mixed results. Some studies show good pain control with TENS, while others show very little improvement in pain with TENS. In 2001, a group called the Philadelphia Panel published a series of papers in the Physical Therapy Journal that gave the use of TENS a grade of "C" (no benefit found) for problems like low back pain, shoulder pain, and knee pain.

Popular Pain Control Methods

Controlling pain is a billion-dollar healthcare industry, and it is estimated that over 20% of American adults are living with chronic pain.

Some methods that people use to control pain include:

Keep in mind that the way you experience pain is very personal and is made up of all of your life's experiences combined with your fears, expectations, and, of course, any sort of physical injury or insult to your body's tissues. This means that your particular pain control method may work for you while it is useless for another person.

Working with your physician to find the best method to control your pain is recommended.

A Word From Verywell

The pain gate control theory is a simple way to understand how you feel pain and how to control acute and chronic pain. Simply put: non-noxious stimuli can get through the gate to your brain while preventing painful feelings from getting to your brain.

This model of pain control can help you find the best approach to eliminating your pain. By working with your physician or medical professional, you can exploit the gate theory and maximize your chances of successful pain control.

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Article Sources

  1. Albright J, Allman R, Bonfiglio RP, et al. Philadelphia Panel evidence-based clinical practice guidelines on selected rehabilitation interventions for low back pain. Phys Ther. 2001;81(10):1641-74. doi:10.1093/ptj/81.10.1641

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