What Is Pain? Pain Basics 101

It’s common to hear “the pain is in your head” as an attempt to motivate hurt or injured people to overcome their injuries, implying the pain doesn’t actually exist and it is simply being perceived. This mentality is very prevalent in the athletic and tactical environments. Turns out, it’s true that pain is in your head, and we aren’t talking about direct trauma to the head like in the video above. Here is a simplified crash course in Pain Basics 101.

Pain perception is very complex. The body’s nervous system contains special nerve fibers whose primary role is to identify what the body may perceive as a painful threat to its tissues. These receptors (nociceptors) trigger the nerve to send a signal from the point of stimulus (ex: hand touching fire) to the spinal cord where two things happen: 1) a reflex signal is immediately sent back through the peripheral nerves to the motor units to instinctively move into a safer position (pulling hand away from fire), and 2) a signal travels up the spinal cord to the brain for more complex processing. The pain signal hits the thalamus which further relays the signal to other areas of the brain including the parietal lobe (sensory processing), limbic system (emotional processing), and the cerebral cortex (higher-level executive processing). Through this, we have the actual sense of the harmful stimulus and being in pain (ouch!), establish an emotional response to it (scared, sad, mad, etc.), and learn from the experience through cerebral processing and memory formation (if I touch the fire, then this is what happens). This upper level functionality allows us to adapt and learn so we know not to do it again next time.

So, as the above paragraph implies, pain is useful and informs us of a bodily threat. It keeps us alive. However, like most things in life, too much of it can be detrimental and become a maladaptive response. When an injury occurs, the experienced pain comes from the damaged tissues which then undergoes a remodeling, healing phase. The human body is amazing with the ability to adapt and restore. Eventually, given enough time, the damaged tissues will heal. The time from initial injury to tissue restoration is referred to as acute pain and typically lasts a few days to three months, depending on the injury. For most, the pain resolves when the tissues are healed. However, sometimes the pain lingers long after the initial healing phase. This is chronic pain. And it sucks.

I see chronic pain occurring two ways. First, chronic pain can occur if someone constantly re-injures themselves (commonly referred to as acute on chronic pain). This is similar to picking at a scab and never letting the wound fully heal. For example, an overhead athlete with chronic shoulder pain continuing to impinge their rotator cuff with pressing movements because they are 1) too stubborn to modify the aggravating activity, and 2) unwilling to put time and effort into correcting the mechanical faults. This type of pain syndrome physiologically resembles acute pain but can be classified as chronic due to overall symptom length. Basically, it is a perpetual problem and simply kicks the can down the road.

The second chronic pain pathway is more common and far more complex. Therefore, it is more challenging to overcome. This is perceived pain despite tissue healing. It is no longer about the anatomical structure but more so the neural, hormonal, and psychological components. Simply, the pain has placed the body’s systems out of homeostasis. As previously mentioned, the human body is amazing and very adaptable; however, the adaption can become maladaptive. For example, let’s look at the nervous system. For individuals with chronic pain, the nociceptors and pain fibers, which are primarily at rest without a painful stimulus, become either hypersensitive to normally non-painful stimuli (ex: light touch), and/or constantly active despite a lack of stimulus (ex: constant pain, even at rest). Whether or not there is a true threat to the body, these nerves are sending an onslaught of pain signals to the brain. Unfortunately, the brain does not recognize these nerve fibers have become dysfunctional and continues to process the message as a potential threat.

Chronic pain’s effect on the hormonal and psychological components are better addressed in a separate article.

This article only touches the surface of the complexity that is pain. I, by no means, claim to be a chronic pain expert as I am learning more and more each day. Honestly, a reason we decided to do a series on this topic was to force me into deeper exploration on it to get a better understanding so I may better treat my patients (and myself). Hopefully this information will be useful to others, as well.

Thanks for reading.

- Pat

Romans 5:3-5 (NIV)

Not only so, but we also glory in our sufferings, because we know that suffering produces perseverance; perseverance, character; and character, hope. And hope does not put us to shame because God’s love has been poured out into our hearts through the Holy Spirit, who has been given to us.

#chronicpain #physicaltherapy #pain

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