The Brain, Nervous System, & Stress

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I love my mindfulness and stress reduction with a HUGE dose of science and research… and I hope you do, too!

In the video below, I explain the brain science, nervous system architecture, and stress-response research that inform the practices we will be using in this class. Enjoy!

Summary of Key Points

In essence, our nervous system must do two things:

1. assess if there are risks present
2. respond accordingly — if a risk is detected, defense mechanisms must be deployed; if the environment is safe, the primitive defense systems must be inhibited

Our brain and nervous system are generally pretty accurate (think of how often your “gut instincts” have been correct), but sometimes they are a bit overactive in detecting problems … and then we live in a perpetual stress response.

The Polyvagal Theory referenced in the video proposes, as psychiatrist Stephen Porges states, that our “physiological state limits the range of behavior and psychological experience.” If we are activating the sympathetic nervous system in response to a real or perceived threat, our behavioral repertoire is limited, and we will generally revert to “auto-pilot” (and often “reptilian”) responses.

STRESS can be defined as a state in which homeostasis has been disrupted and behavior becomes disorganized. What we experience physically as stress are the shifts in the nervous system in response to stressors (increased heart rate and breathing, muscle tension, inhibition of digestion, etc.)

Stephen Porges adds that the defining characteristic of stress, however, is not simply the stress response itself, but our “physiologic state of vulnerability” — meaning the strength and resiliency of our parasympathetic nervous system. The parasympathetic nervous system is responsible for the “rest and digest” mode — slower heart rate, slower rate of breathing, reduced muscle tension, a “resting” of the vital organs, resumption of digestion, and the general growth and restoration processes of the body.

The Two Branches of the Autonomic Nervous System

If we can strengthen what is called “vagal tone” (explained more in the next video) by learning practices to engage the parasympathetic nervous system and bring the “rest-and-digest” mode back online, we can increase our stress resiliency.

So let’s practice!

Continue to the next lesson…