Most people know the sympathetic nervous system. It’s how we handle stress – via fight or flight (and I would add freeze into that mix). The Sympathetic nervous system (SNS) is activated not only when we are stressed but also when we are in danger or are physically active. The effects of the sympathetic nervous system include an increase in heart rate and breathing ability. It also slows down processes like digestion.
What is the sympathetic nervous system (SNS)?
Part of the autonomic nervous system, the Sympathetic nervous system could be called your ‘automatic’ nervous system because it’s responsible for many bodily functions that you don’t have to think about to control. These functions control heart rate, blood pressure, digestion, urination, sweating and several others. We are generally familiar with the sympathetic nervous system as it relates to our stress responses. In such situations, the SNS kicks into high gear, speeding up your heart rate, delivering more blood to areas of your body that need oxygen and any other responses you need to help you get out of real or perceived danger.
What is the function of the Sympathetic Nervous System?
As mentioned before, the sympathetic nervous system (SNS) controls your flight, fight or freeze response. Depending upon how you react to stress or perceived (or real) dangers, certain things may happen in your body such as:
- Pupil dilation to let in more light and improve your vision.
- Increased heart rate which improves delivery of oxygen to other parts of your body.
- Relaxed airway muscles so as to improve oxygen delivery to your lungs.
- Slowed digestion so energy used in this body process gets diverted to other parts of the body.
- Activation of energy stores in the liver so that they can be used quickly.
This all occurs to help you in situations in which you may need to think or act rapidly. Your eyesight, reflex, endurance and strength are sharpened so you can ward off attack. The SNS can also be activated when your body is under other types of strain such as stress or illness.
Neurotransmitters and the SNS
There are three specific neurotransmitters, also known as your body’s chemical messengers, that play an important role in the Sympathetic Nervous System. They are acetylcholine, epinephrine and norepinephrine.
Acetylcholine plays a role in regulating heart rate, blood flow and digestion.
Epinephrine is more commonly known as adrenaline. It is, therefore, both a hormone and a neurotransmitter. A small amount of this neurotransmitter is produced by the nerves, but it still plays an important role in attention, focus, excitement, metabolism and panic.
Norepinephrine is also a hormone and a neurotransmitter. You may know it by its hormonal name, noradrenaline. This substance is made from dopamine, the neurotransmitter that controls both pleasure and pain. Norepinephrine does the following:
- Increases alertness, arousal levels and/or attention.
- Constricts blood vessels to regulate blood pressure during stressful situations.
- Affects mood, memory and your circadian rhythms (sleep/wake cycle).
Where is the Sympathetic Nervous System located?
Most of the signals in the SNS start in your spinal cord. These signals leave the spinal cord and activate the ganglia. Your sympathetic ganglia is like a network throughout your body, that sends signals far and wide to different parts of your body such as the heart, lungs, arteries, sweat glands and digestive system. The main type of cell in the Sympathetic Nervous System is a neuron.
What conditions can be caused by a dysregulated Sympathetic Nervous System?
As you’ve seen in this article, the SNS has a big impact on bodily functioning. Common conditions related to sympathetic nervous system dysfunction include but are not limited to:
- Type 2 Diabetes.
- Chronic Stress.
- Anxiety and panic disorders.
- Cancer.
- Sexual dysfunction.
- And Trauma.
In order to avoid such health problems, you can take some necessary steps to safeguard your health. One such step is to eat a healthy, balanced diet full of fruits, vegetables, high quality protein and fiber. You should also abusing substances like alcohol or drugs. You will want to remain physically active by exercising regularly and work on keeping your weight at a healthy level. When in dangerous situations, please wear safety equipment to protect yourself from any nerve damage that injuries may cause. Finally, you’ll want to manage any chronic health conditions so that you can be at your best. If you have questions on how to do just that, please reach out to a qualified health care professional.
Deanna Goodson 