If you are a person with chronic pain, your doctor or physiotherapist probably told you
that you need to exercise, right?
But, are you the kind of person who doesn’t see any benefit in exercise?
Or the contrary, your pain gets worse with exercise.
So what is going on?
There is a scientific reason why some people with chronic pain do not have an analgesic
benefit from exercise.
So, let’s talk about the paradoxical effect of exercise on chronic pain
When we exercise, like walking, running, or lifting weights, our muscles are connected
to the nerves, and these nerves will bring this information to the spinal cord.
Here in the spinal cord, the nerves will bring electrical impulses that will connect in the
spinal cord, and then they will go up to the brain and inform the brain that you are moving
many muscles of your body.
We are not supposed to feel pain when we run, or walk or we would stop doing these activities.
The brain will then make connections, neurons will start talking to each other in the brain
and make these connections, they are called synapses.
Then, the brain will send messages down to suppress pain.
This part of the brain looks like the trunk of a tree, holding the brain here is called
the brain stem.
The brain stem is very important.
Here there are neurons that produce our endogenous analgesics.
This area is known as our inner pharmacy.
The neurons here are capable of producing opioids, serotonin and cannabinoids.
Yes, all these are potent analgesics.
Opioids are endorphins, enkephalins and dynorphins.
Serotonin is the neurotransmitter of happiness and combats depression.
Cannabinoids are potent analgesics and also cause euphoria.
What I just described is a top-down mechanism to suppress pain.
In medical terms, we call these the descending inhibitory pathways.
It is a brain mechanism to inhibit pain.
Before I continue, let me remind you that this video is not intended to replace medical
advice.
If you have a condition that needs medical advice, please talk to your doctor.
This video is for educational purposes only.
If there is an emergency, please go to the nearest emergency department or call an ambulance.
Have you heard of runners’ high?
Yes, some runners produce a lot of analgesic substances in their brain that they get euphoric
and high.
We know that the runner’s high is related to the release of opioids because if we give
naloxone to these runners, they don’t feel this euphoria.
Naloxone is a substance that blocks opioid receptors.
Naloxone is used as an opioid antidote.
So, when these substances are released, they are distributed to various parts of the body,
and the person feels good, no pain, the serotonin will help them to sleep well, and that is
what we call “post-exercise analgesia”.
However, in people with chronic pain, this inner pharmacy is not working correctly.
How do we know that?
There are some tests that we can do with people who have chronic pain to see if they are able
to activate this inner pharmacy in the brain stem.
One of these tests is called conditioned pain modulation.
This test show how much activation of the brainstem the person is capable of.
Athletes are able to activate the brainstem areas and produce a lot of analgesic substances.
The amount of activation of this brain pharmacy is directly proportional to the levels of
physical activity of the person.
An interesting fact: estrogens contribute to this pain caused by exercise, so women
have a higher chance of having pain after exercise than men.
Another interesting fact: the scientists tested people who had knee arthritis and were scheduled
to have knee replacement surgery.
Those who were able to activate the brainstem with exercise as demonstrated by the tests
of conditioned pain modulation did much better 6 months after surgery, they had greater pain
relief than those people who did not do well in the conditioned pain modulation tests.
In some pain patients, especially people with fibromyalgia, do not have the ability to release
these substances in their brainstem.
Not everyone with fibromyalgia is like that.
So, when they do some vigorous and fatiguing exercise, they don’t have the release of
these substances and they feel pain, a lot of pain after exercises.
So far, we talked about the top-down mechanisms, the descending inhibitory pathways.
I have to mention now the ascending pain pathways.
The bottom-up pathways.
I explained in another video that the pain system can also become sensitized.
Central sensitization is a bottom-up problem.
The peripheral nerves and the spinal cord are sensitized.
They amplify the painful sensations, and the brain gets information that is exaggerated.
This mechanism involves the NMDA receptors in the pain system.
Scientists can measure how much sensitization a person has by doing a test called temporal
summation.
And here, the studies also show that people who do more exercises, aerobics and isometric
exercises, they have less temporal summation, therefore, less central sensitization.
So, in practical terms, a person with chronic pain has more sensitization and less pain
inhibition.
Their brain receives more messages of pain because of sensitization.
And their brain is incapable of activating the brainstem to release endogenous analgesics.
Now, listen to this, as this is very important.
Do you know what is the best ways to revert these problems?
How to make the brainstem produce these substances normally again?
And how to reduce central sensitization?
Yes, the answer is exercise.
So, how do we do that?
It is simple.
People with chronic pain, especially those who have central sensitization should avoid
doing vigorous exercise, like any exercise that will fatigue the muscles.
Avoid doing intense exercise that leads to fatigue.
Instead of doing vigorous and fatiguing exercise once in a while, the best way to fix this
problem is if you practice regular exercises, starting with low intensity, and short duration,
and increasing gradually, increasing the intensity and duration.
But it has to be gradual.
You will not notice the effects immediately.
It will take time for your brain to adjust.
So, next time when you are doing your daily exercise routine, think like this, you are
not only doing exercises for the range of motion, to get stronger and more flexible,
you are retraining and fixing your pain system.
I have another video in that I give a recipe for exercise for fibromyalgia.
I show how to start and I give a handout to follow and increase the intensity of these
exercises over a 4-week period.
This exercise routine works for any person who has chronic pain and feels that exercise
is not really giving them the analgesia they expect.
It is possible to retrain your brain stem to produce these analgesics, endogenous opioids,
serotonin and cannabinoids.
Exercises reduce NMDA receptor activation, which then reduces central sensitization.
Exercise promotes a balance between the bottom-up and top-down pain systems.
So, don’t waste time and start your exercise routine today.
Goodbye