Pain is our perception of discomfort and is an important, adaptive response of our nervous system which helps protect us from further injury. Pain sensitivity increases after an injury due to the chemical responses in the target tissue (tissue that is disturbed or injured). This increased sensitivity is normal and an important part of the recovery process.
Pain triggers inflammation which directs healing cells to the area of injury. The pain message is carried on nerve fibers called A fibers which are large in diameter, which allows messages to travel quickly. After the pain message reaches the central nervous system (brain and spinal cord), a response is generated that creates new ion channels along the C nerve fibers. The more ion channels the C fiber has, the more sensitive we are to pain. So in a sense, pain begets more pain, and that is how we become sensitive to any touch in our toe after we stub it. Over time, as the inflammatory process completes and healing occurs, the target tissue begins sending “normal” messages back up the nerve and the central nervous system responds by telling the C fibers to decrease the number of ion channels, which decreases our sensitivity to pain. The process just described is best know as the acute pain cycle.
The process just described is what happens in the ideal world, but in some cases the pain message lingers despite adequate healing time, and this process is known as chronic pain. Healing may be slowed due to physiological changes such as inadequate circulation, and poor immune response, both which can make someone more likely to develop chronic pain. In the past, the literature described chronic pain as any pain lasting more than 3 months; however, a movement is beginning in which we are understanding pain as more of a continuum rather than separate categories. The more stress we have on our system whether it be continued overuse of an injured area, or whether it be mental stress or fear of our injury, the more likely the pain message will continue and develop into chronic pain. In the case of physical stress to the tissue, the inflammatory process is stimulated to continue, which results in continued increased sensitization of the nervous tissue and if left unchecked can result in target tissue changes including fibrosis (tissue changes from its original formation such as muscle to fibrous connective tissue). In the case of mental stress, there is more overflow of nerve impulses from the brain to the body (think of our stress tolerance like a bucket that when full spills over in the form of nerve impulses that travel down our nerves from our brain to our spinal cord and out to our body) and the nerve impulses create excessive traffic that results in increased firing of the nerve and use of the ion channels. The body thinks if the ion channels are all being used, that we must need them, so the body keeps the sensitivity of the nerves elevated by hanging on to the excessive ion channels.
In order to tell the central nervous system that we no longer need the extra pain sensitizing ion channels, we need to send messages from the body to the brain that everything is alright. In physical therapy, we do this by moving the body in ways that are not painful, but that are significant enough to send a message to rewrite the pain sensitization response. The good news is that ion channels only live for 2-10 days before they are either replaced or just eliminated, so rewriting our pain response can begin after only 2 days. We usually notice improvement in overall pain with physical therapy by 2 weeks of starting on an appropriate exercise program. If the exercises are too difficult, then the body may perceive pain, and the pain cycle continues. If the exercise is a novel motion not normally associated with pain, but using muscles and joints that are usually painful, then we can successfully disrupt the pain cycle.
Generally, the longer the pain has been around, the longer it takes to completely break the pain cycle. In some cases of chronic pain the brain has created a pattern of pain message activity that becomes perceived as normal, and the brain will continue generating pain messages to fill in the “normal” message of pain despite our efforts to rewrite the messages. In these cases, we find that patients must continue on a long term exercise program to continue the positive input to the system and to continually re-write the pain message to keep it at bay. In some cases even when everything is being done correctly, the pain message is not completely eliminated, and we then educate the patient in how to work around their pain and pace their activities to prevent the pain from flairing up beyond acceptable levels. These patients are sometimes directed to a pain management doctor who can discuss medication that can assist with correcting the chemical process of chronic pain in the brain and nervous system.
We also concern ourselves with the general state of the brain’s firing (factors such as sleep, stress, production of endorphins which are our natural pain killers best produced during outdoor cardiovascular activity).
In physical therapy, we design a program to address all aspects of the pain cycle. We treat the target tissue (muscle, fascia, joint, nerve, tendon, ligament, etc) with manual therapy/hands on treatments and exercises. We rewrite the nerve firing pattern by incorporating movements in a novel, pleasant, and positive environment. We also use electrical machines to send impulses along the nerves to electrically disrupt the pain message or to trigger normal firing in a muscle. We treat the brain by educating patients in how they can control their pain which decreases their stress about their condition and decreases overflow to the body. We educate patients in proper sleep habits/hygiene, stress management techniques, and in the basics of proper nutrition and hydration to keep the physiologic anti-pain processes working at their optimum. We introduce appropriate levels of cardiovascular exercise and whenever we can, humor, to assist with production of the brain’s natural pain killer, endorphin.
For more information, check out Explain Pain (2003) by David Butler and Dr. Lorimer Moseley, Noigroup, Adelaide.
Video Transcription:
Once upon a time all the lands were
fraught with the persistent pain so widespread was this affliction that one
in four people experienced it the pain lasted for more than three months it
shadowed their daily lives held them back from everyday activities and the
interventions they tried proved useless hey pain go away we’ve tried it all but
still you stay moving less taking pills knives and needles and still we’re sore
we can’t take no more no more but the pain remains like a loyal companion the
people’s hopes faded and they became resigned to living with the pain only
now the pain was a beast then along came a group of
researchers of which I am one back off big fella I’m professor Lorimer Moseley
and I’m a pain scientist pain scientists are starting
to think differently about pain and its causes and we’re
making exciting discoveries like how the way you think
about your pain can change the way it feels over the next few minutes I’ll
help you to understand your pain understanding is important because it
can change how much things hurt and how much your body can do and it can help
you to tame the Beast first trust me about this pain is not an
accurate measure of tissue health pain is a protector by making unpleasant feelings
your brain changes your behaviour so you can avoid injury or your tissues can
heal sometimes pain is not helpful like phantom limb pain if you don’t expect a
missing limb to ache but it does and the pain is very real so how do we explain
this well pain is a warning signal from your brain that depends on credible
evidence to say your body needs protecting sometimes pains too
protective and you get unnecessary warning signals paint scientists now
understand that there are many ways our nervous system ends up reducing
unnecessary warning signals take conditioning for example we think of
Pavlov’s dog every time food was offered Pavlov rang a bell of course the
dog will salivate seeing the food which went on for a while eventually the dog
was conditioned to salivate for the Bell alone
conditioning is just one of the ways your body learns pain and the longer
your nervous system produces pain the better it gets at producing it your body
learns pain so what feeds this beast well let’s look at how pain works in
your body’s tissues there are specific neurons which normally only respond to
harmful stimuli whether mechanical chemical or thermal when they are
activated they send a warning signal to your spinal cord which can in turn send
the signal to your brain this activity in neurons is called Nociception and
it’s happening all the time but only sometimes results in pain most
of the time the brain protects you with other things like movement once the
warning signal reaches the brain the brain makes sense of it based on the
information arriving and a vast amount of information already stored if there’s
good reason to think protection is required then your brain makes pain one
of our amazing discoveries is that you can have pain without any physical
stimuli thoughts and places might activate the warning signals and the
pain feels exactly the same it’s not just your brain your spinal cord also
learns how to generate unnecessary warning signals so how do you know when
your nervous system is learning pain you may notice if your pain spreads or comes
on without warning your body feels odd and it’s hard to move properly your pain
changes quickly with your mood and small annoyances can set it off old injuries
start to hurt again you’re more sensitive to stimuli and the
longer the pain goes on the more all of this occurs the old way we understood
pain could not explain these things and left many sufferers feeling like no
one believed it was real or for it to hurt so badly there must be a major
tissue problem but we now know how persistent pain happens so how can you
Tame the Beast pain is a very personal thing there’s no
one-size-fits-all solution and while you probably have well thought out coping
strategies it’s time to take a new approach to dealing with and reducing
your pain one that focuses on retraining your pain system
this might mean testing yourself physically and moving more than you
normally would being honest about your current attitudes and beliefs can also
help as can asking your health professional new questions how do I know
if my pain system is being overprotective how do I retrain my pain
system to be less protective how do I know if I’m safe to move so be brave and
have hope because it is possible to Tame the Beast visit our website for more
information and questions to ask your health professional tamethebeast.org
