Despite obvious associations with injury and pain, they are in fact not the same thing. Research into the science of pain has indicated that pain has a poor correlation with tissue damage.
Pain has been synonymous with injury ever since the 16th century, when a French philosopher called René Descartes theorised that the body was more like a machine. He proposed that tissue damage would pull on a cord attached to a bell in the brain, thus alerting the brain to tissue damage.
Descartes’ theory of pain has changed as anatomy and physiology of nerves were discovered, but a dominating theme remained: Pain = Tissue damage. Despite solid research in the last 20+ years indicating the contrary, this is still the widely held belief in today’s society.
“René Descartes was very, very smart, but as it turned out, he was wrong” – Lorimer Moseley
So what is pain then?
Descartes’ model isn’t completely false. Nerve endings do send messages to the brain. But they don’t send messages about tissue damage, they send messages about danger.
The nerve endings in your skin can be stimulated by mechanical forces (e.g. pinch or pin prick), some respond to temperature changes (e.g. boiling hot water or freezing dry ice on the skin) and some respond to chemical changes (e.g. acid or inflammatory chemicals release by cells).
It is important to realise that these nerve endings are activated by stimuli at a lower intensity required to actually damage the tissue.
- Stubbing your toe can be extremely painful, but it is rare for actual damage to occur and the pain quickly subsides
- Jumping under a hot shower often causes you to feel a burning pain and quickly get out of the way, but your skin hasn’t actually been burnt
- Getting pinched really hurts! But does it actually damage you?
The transmission of these danger messages from nerve endings is called nociception (things that stimulate nociception are call noxious stimuli).
To confuse things further, even the amount of nociception isn’t equal to the amount of pain you experience. This is because pain is about protecting you from threat, like an alarm system, but the amount of protection it needs can change based on a number of factors.
Sometimes the alarm system becomes sensitive, misreads the situation, perceives you are under more threat and goes off unnecessarily. For example:
- If you are stressed or anxious, the brain is under more threat and will think it needs more protection
- If you haven’t been sleeping well, your nervous system will be more sensitive
- If you have hurt your back bending over before, your brain will be more threatened by this movement in the future
- If you had a knee x-ray and are concerned that there is some degeneration, your brain will naturally be more protective of the knee
- If someone has told you that there is a ‘misalignment’ that needs ‘correcting’ the brain will seek more danger information from that area
The brain can even increase the danger messages it receives from the nerve endings based on a combination of these factors (and many more).
This does not mean pain is all in your head. There are physical changes in the nervous system that cause this to happen.
So what does this all mean?
The brain is extremely smart, but sometimes can be a bit dumb and over-protective.
Have you ever noticed that sometimes things that shouldn’t hurt you sometimes does? It may be a minor jolt on the tram that hurts your neck, or picking up something as light as a toothbrush causes your back to hurt.
This further indicates that the nervous system may be just hypersensitive at this time.
Of course pain can be caused by an injury, so it is important to see a practitioner knowledgeable about how pain and the nervous system work to identify what is relevant to your pain (like our Osteopathy and Physiotherapy team at Absolute!).
But the important message here is not to catastrophise if you experience pain. Pain is rarely caused by a serious problem.
Remember pain is a protection mechanism. It is great at letting you know something is going on, but it isn’t good at telling you what is going on. Pain is a motivator to act. To change something. To move more, avoid a movement (for a period of time) or see a practitioner.
To get a quality evaluation of your pain problem, come and see the team at Absolute Health & Performance 199 William Street, Melbourne CBD 3000
Written by Osteopath Matt