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Polyvagal Power: Unraveling the Science Behind Sleep, Anxiety, and Stress

woman doing vagal nerve exercises


If you are someone who frequently searches insomnia, stress or anxiety on the internet, then you have likely heard of polyvagal theory, but do you understand it? Why is everyone suddenly talking about polyvagal theory and what does it have to do with sleep, anxiety, and stress?

Hi, I’m Sherry, and I help people lower stress and improve their sleep.

What is Polyvagal Theory?

First, what does polyvagal even mean? To put it simply, poly means many, and vagal means wandering. This name is a descriptive term used to describe the vagus nerve (which the theory is built around). The vagus nerve is the tenth cranial nerve. It is the longest nerve in the body, and it “wanders” all the way from the brainstem to the colon. The vagus nerve is complex, with many different vagal pathways that connect our brain and vital organs (such as the heart, diaphragm, and digestive system). It plays a crucial role in linking the mind and body. As such, it is responsible for relaying stress signals from the body to the brain and back down again. Think of it as a major highway, and each car on this highway carries an important message, allowing the body and brain to communicate with each other .

The Jekyll and Hyde Phenomenon

Have you ever felt like two different people? There is the nice, calm, loving you. The you who is a wonderful friend, is kind to children, and rescues animals. Then there is the not-so-nice, embarrassing you who screams at other drivers, throws their phone, and basically behaves like a wild two-year-old. If this scenario is not familiar, then welcome to sainthood!

For the rest of us, this Jekyll/Hyde type switch likely sounds all too familiar. How can we be so loving and yet so monstrous?

Polyvagal theory was created to help understand this Jekyll/Hyde phenomenon by focusing on the differences in our behavior and social abilities when we feel secure versus when we are in a state of threat. It aims to shed light on the symptoms linked to trauma and the causes of posttraumatic stress disorder (PTSD) .

The Role of Stephen Porges

Stephen Porges, PhD, who is now a professor of psychiatry at the University of North Carolina, introduced the polyvagal theory in 1994 and went on to establish the Polyvagal Institute. Porges' theory offers psychological insights into the vagus nerves' function in managing emotions, fear reactions, social communication, and forming social bonds through the interpretation of social behavior using the polyvagal perspective .

 Understanding the Nervous System

To understand how the vagus nerve works, it’s first important to have a basic knowledge of the nervous system. Essentially, our nervous system responses fall into two categories: parasympathetic and sympathetic. The parasympathetic system is when we are in a secure, comfortable, and relaxed state. We feel a sense of safety, and it is in this state that our body repairs, digests, and falls asleep.

The sympathetic system is when we are stressed or angry. It is our fight-or-flight response, which developed to keep us alive back when we were still living in caves and at risk of being eaten by bears .

The Vagus Nerve: The Body's Internal Regulator

The vagus nerves' main function is to conduct signals from the parasympathetic system to and from the heart, lungs, and stomach. The vagus nerve has two main parts known as the dorsal vagal and ventral vagal complexes:

  • The Dorsal Vagal Complex (DVC) is linked to basic survival, leading some animals to "freeze" or remain motionless when in danger (that frozen deer-in-headlights response). The DVC also plays a key role in managing our digestive functions.
  • The Ventral Vagal Complex (VVC) is connected to the control of sympathetic fight-or-flight responses as well as self-comforting actions and the social engagement system (depending on if we are in a sympathetic or parasympathetic state).

The part of the vagus nerve that correlates with the social engagement system (SES) innervates muscles in the face and head, which are involved in facial expressions, eye contact, and vocal tone, enabling nuanced social interactions. The theory suggests that when individuals experience feelings of safety, their SES is engaged, allowing them to communicate effectively, establish social bonds, and regulate their physiological state in daily life. Our social engagement system is crucial to our mental health and the ability to overcome traumatic events .

The Three Phases of Vagus Nerve Responses

According to the polyvagal theory, when the body receives new information, the vagus nerve processes signals that determine how we respond. These responses can be broken down into three distinct phases: ventral vagal, sympathetic, and dorsal.

The Ventral Vagal Phase

The Ventral Vagal Phase is known as the social engagement phase or our "true self" phase. In this phase, calm situations enable us to interact and connect with others without feeling threatened. This social connection (smiling, laughing, light touch, and other non-threatening body language) all send cues of safety and help to regulate our emotional responses, bringing us back to baseline in times of stress .

The Sympathetic Phase

The sympathetic nervous system oversees our responses to stress. It triggers the fight-or-flight response, leading us to either face or flee from a situation in search of safety. When we are experiencing a fight-or-flight response, we are in the sympathetic phase .

The Dorsal Vagal Phase

During the dorsal response, a segment of the parasympathetic nervous system triggers a shutdown response when immediate danger is sensed. Its function is to immobilize the body into the freeze response, either to endure or to prepare for a fight or flight .

Polyvagal Theory and Sleep

By now, you might be thinking, “Ok thanks for the science lecture, but what does this have to do with sleep?”

It’s important to understand that our nervous system (and its current state) plays a starring role in whether or not we are in a place to be able to get a good night’s sleep.

When we are triggered by something (the fear of not sleeping or being tired the next day, a fight with our spouse, a stressful day at work, etc.), our body still has the exact same response that it had thousands of years ago when we were being hunted as prey. It doesn’t matter if we know logically that we are okay and will likely survive our current stress; our body does not know that, and it does not have the ability to react a different way. Stimulating hormones (cortisol, adrenaline, and noradrenaline) have already been released into our system, and it takes a minimum of 20 minutes for these hormones to lose their effect and allow the body to calm down .

While fight or flight is the main nervous system response causing disturbed sleep, the dorsal vagal (shut down and overwhelm) can lead to a mixed response. Yes, the body has shut down in an effort to stay safe, but that doesn’t mean it’s relaxed. If you have ever watched an animal startle and freeze (cats do this often), you know there is nothing sleepy about them. Quite the opposite, in fact, as they are keenly aware of the danger, watching for it to pass and preparing to run away .

Nurturing Your Nervous System for Better Sleep

Regardless of how your individual body handles stress, to fully enjoy restful sleep on a consistent basis, it is important to be in a parasympathetic dorsal state. Knowing this can help you to assess the current state of your own nervous system and understand what is happening (along with why).

They say knowledge is power. What can you do differently to nurture and support yourself now that you have a deeper understanding of your body and know that it is acting exactly as it evolved to? Most often, lack of sleep is not a body malfunction, and there is nothing wrong with you. It’s just that the body has perceived a possible threat and is doing its best (regardless of how inconvenient and uncomfortable it may be) to keep you safe .

Somatic Exercises and Polyvagal Theory

The development of polyvagal theory and its rise in popularity has led to an abundance of self-help somatic-type polyvagal theory exercises to help rebalance and fine-tune our nervous system. These are based on Dr. Porges' concept of "neuroception," which describes the various responses of the nervous system to signals of safety and threat. He emphasizes that neuroception happens without our direct knowledge (for example, we can see someone frown and interpret that as a threat (they are mad at us), which then triggers a stress response before we are even consciously aware of the thought).

While this may sound daunting (we are constantly being triggered!!), it’s important to remember that these signals work both ways. In other words, we are also capable of noticing signals of safety, such as smiles, hugs, and sounds of nature. By becoming more conscious of the alterations that happen during neuroception, such as a faster heartbeat, a slumped stance, and changes in breathing, we can become more aware of changes in our nervous system. Upon recognizing these indicators, we can start to react in a manner that enhances our sense of security .

Practicing Polyvagal (Somatic) Activities

Polyvagal (somatic) activities are designed to assist you in monitoring changes in your nervous system and practicing strategies that regulate it. Examples of these activities include deep breathing, exposure to cold temperatures

or cold water, meditation, physical exercises such as tai chi, and singing .

A word of caution: While it is an act of self-care and kindness to support your body, it is important to do these exercises with proper intention. Performing any activity for the express purpose of “making yourself sleep” is likely to backfire. This is because sleep is an autonomic process (we can’t control it), and the more we try, the more sleep-related stress we generate (pushing our system into ventral vagal fight-flight mode). The fact is that there is no activity that will guarantee sleep .

So, what is the best way to practice these exercises? I often tell clients that somatic and relaxation exercises (breathwork, ear massage, etc.) are like going to the gym to build a bicep. You would never go for one monster session after years of inactivity and expect to show up for your date looking completely ripped! Instead, you work consistently, day after day, to make the changes you want over time.

If you are stressed, anxious, or can’t sleep, then likely your nervous system has been under stress for a while now, and it takes time and consistency to help it adapt and rebalance (we are repaving the highway!). Filling in potholes, adding lanes, and (just like road work) restructuring and balancing the nervous system takes time!


Interested in Learning More?

If you would like to learn more or book an individual session, please visit the Work With Me page or enroll in the 30 Day Beyond Sleep Course

In the meantime, I would like to leave you with this important message. You are not broken! You are whole, perfect, and healthy exactly as you are, and you CAN sleep!


1. Porges, S. W. (1994). "The Polyvagal Theory: New Insights into Adaptive Reactions of the Autonomic Nervous System." *Cleveland Clinic Journal of Medicine*.
2. Porges, S. W. (2011). *The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation*. W.W. Norton & Company.
3. Dana, D. (2018). *The Polyvagal Theory in Therapy: Engaging the Rhythm of Regulation*. W.W. Norton & Company.
4. Ogden, P., & Fisher, J. (2015). *Sensorimotor Psychotherapy: Interventions for Trauma and Attachment*. W.W. Norton & Company.





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