Simply put, the nervous system is an alarm system. But it’s not entirely that clear cut. Let’s say you were crossing the street and sprained your ankle. Ordinarily this would hurt but let’s also say a large bus is coming toward you. Would your ankle still hurt? The answer is of course not! In this situation, it would not be smart for the brain to produce pain because it would hinder your ability to get out of the way of the bus. The brain would decide that the bus was a bigger threat than the ankle sprain and would therefore not send the signal of pain. This is how people with a broken leg can escape a burning car. This is also why some people don’t feel their pain until after they have stopped working, gardening, playing etc.
The brain evaluates all threats, not just tissue damage. Nerves have receptors for temperature, stress, blood flow, movement, pressure and immune responses. A change in any of these can be interpreted as a threat and thus cause pain in the body. This is why people experience more pain in colder temperatures, with stagnant postures, during times of high stress and when you are fighting off the common cold.
Have you wondered why you are the one that ended up with chronic pain while your friend Sally who was in the same car accident with the same injuries walked away pain free? Every brain is different and processes pain differently. It has been shown that multiple areas of the brain are involved in a pain experience. These areas include those responsible for sensation, movement, focus, concentration, fear, memory, motivation and stress. Each of these areas communicate with each other to discuss and determine the appropriate action. Its like a board meeting takes place to discuss the danger messages. If it is decided that there is a threat and an action is required, pain will be produced to protect you. The members of the board and the decision made will be different for each individual.
Aside from the brain, people experience injury in very different life environments. Someone who is in a car crash during a happy time in life will have a lesser pain experience than someone going through a divorce and layoff. Stressful life environments produce stress chemicals throughout the body that will cause the nervous system to wake up quickly, be extra-sensitive and take a long time to calm down. This is why people who get injured at work (especially at stressful jobs) have slower recoveries than someone injured at a soccer game or a destruction derby driver who crashes cars for fun.
My point here is that it is complicated. Pain is not as simple as you have an injury, it causes pain, the injury heals, the pain goes away. Confused yet? Don’t worry, you’re not alone! This very fact makes my job a million times more difficult! But the great news is this: research has proven that simply knowing pain is complicated, can and likely will reduce your pain if you are experiencing pain for reasons other than damaged tissues. Thank goodness!
Louw A, Puentedura E. Therapeutic Neuroscience Education: Teaching patients about pain. Minneapolis, MN: OPTP; 2013. Textbook.
Moseley, G.L., A pain neuromatrix approach to patients with chronic pain. Man Ther, 2003. 8(3): p. 130-40. Web. FULL TEXT
Gifford LS. Pain, the tissues and the nervous system. Physiotherapy. 1998;84:27-33. Web. FULL TEXT
Louw A, Zimney K, O’Hotto C, Hilton S. The clinical application of teaching people about pain. Physiotherapy Theory and Practice. Jul 2016;32(5):385-395. Web. FULL TEXT