You can think of the nervous system as the body’s electrical wiring. It is made up of the brain, spinal cord, and nerves. Together, this complex communication system controls movement within the body.
- The Central Nervous System (CNS) is the main control center. It is made up of the brain and spinal cord.
- The Peripheral Nervous System (PNS) is made up of all the nerves outside of the brain and spinal cord.

The PNS can be subdivided depending on which type of muscle it innervates and whether that muscle is controlled voluntarily or involuntarily.
- The Somatic Nervous System (SNS) is associated with the voluntary control of body movements via skeletal (e.g. leg, arm) muscles. When you push yourself to exercise harder or faster, you are training the motor branch of your SNS. When you put on a soft sweater or accidentally touch a hot pan, the sensory branch of your SNS tells you what it feels like.
- The Autonomic Nervous System (ANS) is responsible for controlling systems in your body that occur without your conscious awareness – such as your heart beating, lungs breathing, and pupils dilating.
Side note: Good news! Although these systems work without conscious input, you CAN control them if you put your mind to it. Read more here! (link to Deep Breathing Improves Digestion)
The ANS has two main divisions, sympathetic and parasympathetic. This is where it gets interesting!
- The sympathetic branch of the ANS is responsible for our “fight-or-flight” response. This reaction to a stressful event (e.g. seeing a bear in the woods) helps get your body moving by increasing blood sugar, heart rate, and by directing increased blood flow to your cardiac (heart) and skeletal (leg, arm) muscles.
- The parasympathetic branch of the ANS is responsible for your “rest-and-digest” response. This mode helps you conserve energy by decreasing heart rate, blood pressure, and respiration, and by allowing blood flow to return to the digestive and reproductive organs. This response improves digestion by increasing secretions (e.g. enzymes) and peristalsis (i.e. movement) of the digestive tract, and nourishes the reproductive organs.
Which state do most of us live in?
Sympathetic.
Which state do we want to be in more often?
Parasympathetic.
Why?
Spending more time in parasympathetic mode results in:
- Better digestion
- Increased fertility
- Healthier blood pressure
- Healthier blood sugar levels
- More stable mood
- More energy
- And more!