At some point in our lives, each and every one of us will experience this strange thing called pain, whether physical or emotional. Experiencing pain is part of conscious living, it is part of being human. The question is – What exactly is pain? Is it as simple as “pain = tissue/body damage”? (eg. If my back hurts, there has to be something wrong with my spine)
The purpose of this post is to help you understand what pain actually is, as I strongly believe that understanding pain will help change your perception of pain, allowing you to have better capacity to deal with pain and be able to make better decisions on how to respond and manage pain, making it a crucial part of the recovery process.
What is pain?
Pain is defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”.
The key word in that definition is an “experience associated with actual or potential tissue damage”. Basically, pain is created as an output of the nervous system (brain, spinal cord) in response to perceived threat from bodily tissues and the environment, however not always (but can be) actual threat. Pain occurs when credible evidence of danger related to our body is greater than our credible evidence of safety related to our body. Essentially, pain acts as an “alarm system” of the body, a protective mechanism to warn you that there is a potential threat, it is NOT a direct interpretation of how much damage is present. Pain does not come into the body and up to the brain, it is a response produced by the brain, and this response can be influenced by many factors that I will cover later in this post.
Consider this simple scenario – You reach out to touch a boiling kettle, the moment you contact the kettle, a signal from sensors in your fingers is sent to your brain and your brain processes it, and deems it as a threat due to its excessively high temperature that can potentially burn you if you leave your hand on it. The brain then creates a pain response which makes your instantly draw your hand back. You move on with your life with no actual damage to the hand at all. Pain is considered a helpful response in this case.
Here comes the confusing part – Pain, although in many cases can occur as a result of tissue damage (eg. High grade ankle sprain, ACL rupture, acute fracture) , can also be present in individuals with no real tissue damage. Studies have demonstrated that people with actual tissue changes in the body identified by MRI’s can experience NO pain at all (eg. disc buldges, arthritis, tendon changes, rotator cuff tears). This brings up the question – does pain really equal tissue damage? Are levels of tissue damage directly correlated with pain levels? Evidence suggests otherwise- Tissues can be sensitive with no presence of real damage. Pain is not just all about tissue damage itself, many contributing factors can drive tissue sensitivity.
The concept of tissue sensitivity
To understand the concept of tissue sensitivity, let’s go back to the analogy of pain as an “alarm system” in your house, the purpose of this alarm system is to ensure that no one breaks in.
Let’s consider 2 scenarios:
- During acute traumatic injury (eg. ACL rupture) – This “alarm system” is activated as a result of tissue irritation/damage (someone breaking into your house), in order to protect the region and pain is produced. This is a helpful response in an acute situation that stops you from further irritating the region, to allow the region to heal.
- In a persistent case where there was an acute injury at some point earlier on (or even sometimes no actual acute injury), but pain continues to persists after the structure has healed – the body has the ability to learn to be more protective, thus increasing the sensitivity of this “alarm system”.
What this means is that the “alarm system” can go off even when no one is trying to break into your house, it goes off even if it starts raining and rain droplets contact the windows. Protection can be overamplified, which is unhelpful in this case. The longer pain persists, the less it has to do with structural damage, and the more it has to do with potential drivers of sensitivity.
This isn’t to say that the pain isn’t real in this case, it is very real, it just means that you should be looking at other factors that could be driving the sensitivity other than purely structure.
Drivers of sensitivity
There are a multitude of factors that can drive sensitivity and increase the pain experience in individuals, tissue structure being just one of them. Structure is definitely an important factor and not to be missed especially in acute cases, but so are these other factors as it can act to “wind up” sensitivity, resulting in an amplified pain response.
- Unaccustomed loading (too much, too soon)
- Deconditioning/poor load tolerance of structure
- Lifestyle factors: Poor sleep, recovery, diet
- Negative beliefs and attitudes about pain and injury
- Fear avoidance behaviours
- High psychological distress
- Poor coping strategies
The overflowing cup
The overflowing cup analogy adapted from Greg Lehman – The pain experience can be viewed as the overflowing cup, many factors that have the potential to drive sensitivity can fill the cup, if there is a sudden increase in a stressor or a new stressor (whether physical or psychological load/stress) that tips you over the edge, spilling the cup, pain can potentially emerge.
Think back to a time when you’ve had an onset of pain – Was there a change in stressors? Were you having poor sleep quality or poor sleeping patterns out of your norm in that period of time? Was your training load higher than usual? Was life more stressful at that period of time?
Perhaps you’re experiencing pain now, have a think about these contributing factors and see if it applies to you. Identifying these factors will be a good start for you to come up with a plan to address them. Every individual’s pain experience is different, 2 people with the exact same condition can have totally different contributing factors and pain experiences.
The purpose of this post is introduce this concept of pain and sensitivity, to help you understand what pain is and the multidimensional nature of pain. This is certainly not a topic that can be covered in one post.
The key messages here being
- Pain doesn’t equal tissue damage – A fire alarm doesn’t exactly tell you how big the fire (threat) is
- Pain is a protective mechanism of the body, an output of the nervous system
- The body’s “alarm system” can adapt to be too efficient in producing a pain response
- Structures can be sensitive and painful with no real damage – a structure can be sensitive in particular positions, loading, movement patterns, but not actually damaged – you’re not as broken as you think, there is hope.
- Your body is adaptable, there are ways to desensitize your structures to sensitive positions/movement patterns
- Identifying contributing factors and learning how to manage them well needs to play a key role in pain management
- Pain is a very personal experience and varies person to person – What is making your cup overflow?
- This post is to provide an understanding of pain, it is not aiming to provide a diagnosis. If you’re experiencing on-going pain, a visit to a reliable healthcare professional for screening will be a great idea.
A few extremely helpful resources can be found here
- Greg Lehman’s pain guidebook is a great resource that gets more in depth on the understanding of pain and tools to help with self-management – Pain Science Guidebook
- Butler D, Moseley GL. Explain pain. Adelaide: Noigroup publications, 2013
- Moseley GL, Vlaeyen J. Beyond nociception: the imprecision hypothesis of chronic pain. PAIN. 2015;156 : 35-38.
- Woolf CJ. What is this thing called pain? Journal of Clinical Investigation. 2010;120 (11):3742-3744
- Nicholas MK, Ashton-James C. Embodied pain: grasping a thorny problem? PAIN. 2017;158(6):993-994.
- Lehman G. Recovery Strategies. Your pain guidebook. http://www.greglehman.ca/pain-science-workbooks