Your SNS stimulates your nerves and the rest of your body in many of the same ways that the parasympathetic nervous system suppresses your reactions.
"Fight or Flight" Response
The SNS is the system that stimulates your "flight or fight" response. It serves many important functions that have helped people survive stressful situations for thousands of years.
When you are confronted by danger your SNS will stimulate the release of excitatory neurotransmitters, and stress hormones like cortisol, that will sharpen your senses and speed your reactions.
When your caveman ancestors were confronted by an enemy or by a saber tooth tiger, it was his SNS that allowed him to react faster and made his muscles stronger so he could escape or conquer the threat.
Life without Saber Tooth Tigers
In todays modern world, without saber tooth tigers, your SNS is likely to be stimulated by your morning commute, or a confrontation with your boss. Your stress reaction can also be turned on (or off) by your thoughts.
Thinking about stressful situations or dwelling on worrisome subjects will flood your body with excitatory neurotransmitters and stress hormones like cortisol. These will cause the same reactions within your body that your ancestors had when confronting the saber tooth tiger.
During times of Stress Your SNS will:
• Dilate Your Pupils
• Increase Your Heart Rate and Breathing
• Divert Blood Flow to Your Muscles
• Increase Your Blood Sugar
• Release Adrenaline and Cortisol
Unfortunately, when you are living with chronic pain stimulating your SNS will make your pain worse.
Making your nerves more sensitive and faster reacting makes your pain even bigger and sharper.
Your parasympathetic system reacts in the opposite way. It will release inhibitory neurotransmitters and reduce your levels of stress hormones.
Image thanks to Nervous ned via Wikimedia Commons
This suppresses your nerve sensitivity and reduces your pain.
This is why things that stimulate your parasympathetic nervous system, like meditation or deep breathing exercises, will reduce your pain.
Your sympathetic nervous system is a very complex system composed of many different nerve cells or neurons. Sometimes these nerve cells can be injured or just spontaneously quit working correctly causing pain.
They can sometimes just start sending a pain signal to your brain or making other changes in the things they control (such as sweating or heart rate or dilating blood vessels) without any visible cause.
The reasons for these malfunctions of the sympathetic nerves have been studied for years but are still not well understood. Also, the treatments for these problems are few, and they do not always work, and when they do work they may not always last.
Some examples of these sympathetic nervous system syndromes are listed below.
Complex Regional Pain Syndrome
Sometimes after an injury or after a surgery, and sometimes spontaneously, the sympathetic nerves can begin or continue sending the pain signal without any discernable cause.
This is Complex Regional Pain Syndrome and it can cause pain that is severe. You may feel burning pain, or a needles and pins sensation, or a tight tourniquet pressure kind of pain.
Raynaud's syndrome is caused by an overreaction of the SNS to cold or stress causing a reduction in the bloodflow to your extremities.
You may experience painful numbness along with discoloration in your fingers or toes from the limited bloodflow.
Chronic Abdominal Pain
Many different things can cause abdominal pain and one of them is a dysfunction of the SNS
Excessive sweating can be from overactivity of the sympathetic nerves.
A doctor specially trained in pain management can block the sympathetic nerves that are causing the problem.
Sympathetic Nerve Block
Local anesthetic and steroid medication can be injected around the sympathetic nerves to block their activity. Unfortunately, these treatments do not always work, and they do not always last.
These injections seem to work best for conditions that have only recently began and they are less helpful for problems that have been present for months or years.
Anti-seizure medications (gabapentin, Lyrica) and anti-depressants (amitriptyline, Cymabalta) can sometimes be helpful because they have an effect on neurotransmitters and nerves. Unfortunately, these too are less than 100% effective.
Narcotic pain medicines can be helpful but they can have significant side effects.
Spinal Cord Stimulation
An implanted device that uses low voltage electricity to interrupt or scramble the pain signal as it travels to the brain has been helpful in some cases.
A Complex System
The sympathetic nervous system is an important set of nerves that has been helping people respond to dangerous situations for thousands of years. It is a complex system that is not well understood and when it malfunctions there can be problems.
When you are living with chronic pain nothing is likely to make your pain go away completely. However, learning how to suppress your SNS and stimulate your PSNS can go a long ways toward making your pain more tolerable.
Researchers at the University of Michigan Medical School Chronic Pain and Research Center teach these relaxation techniques to their patients with this program: