Polyvagal Theory Explained: Understanding Your Nervous System
Diamond and graphite are both made of pure carbon. And yet one is the hardest naturally occurring material on Earth that can cut through steel, while the other is so soft you can rub it off onto paper. The carbon atoms in both are the same – they’re just arranged differently due to differences in the conditions they form under.
That is exactly how your nervous system is, too. It consists of nerve cells that arrange themselves differently depending on the conditions you are in.
The polyvagal theory explains that the automatic part of your nervous system can operate in three different states, which are:
- The ventral vagal state.
- The sympathetic state.
- The dorsal vagal state.
But what do we mean by these states? How different are they in terms of the way you behave in each? The polyvagal theory answers all these questions.
On this page, we explain what polyvagal theory is and how it relates to mental health.
What Exactly Is the Polyvagal Theory?
The polyvagal theory was developed in 1995 by Dr. Stephen Porges, a neuroscientist.
The idea of the theory is based on the vagus nerve, a long nerve that runs from your brain down through your gut, heart, and pelvis. It essentially connects your brain to your heart, lungs, and digestive system.
The vagus nerve is part of the autonomic nervous system. The key role of the autonomic nervous system in the body is to control automatic functions like your:[1]
- Heartbeat.
- Breathing.
- Digestion.
- Stress responses.
The polyvagal theory describes that the autonomic nervous system scans your surroundings for signs of safety or danger, and it shifts your body into different states to help you survive.[2]
Three Nervous System States According to the Polyvagal Theory
According to the polyvagal theory, your nervous system tends to move between three main states:
- Vagal ventral state.
- Sympathetic state.
- Dorsal vagal state.
Ventral Vagal State: Safety, Connection, and Social Engagement
The ventral vagal state is also known as the “rest and digest state.” It is most activated when you are in a relaxed state, for example, when catching up with an old friend over coffee and laughing so much you forget to check your phone.
When the body is relaxed, it has the energy to connect with other people, solve problems, learn new things, and enjoy life.
In the ventral vagal state:
- You feel calm.
- It’s easy to have conversations.
- You can laugh, make eye contact, and feel close to others.
- Thinking comes more clearly, and you can make decisions without feeling overwhelmed.
- Your breathing and heart rate are at a steady rate.
Sympathetic State: Fight or Flight Response
The sympathetic state is known as the “fight or flight” response. When your nervous system detects any sign of danger, it prepares you to either confront the threat (fight) or escape from it (flight).[3]
During sympathetic activation, you have:
- A racing heart, and your breathing is faster than usual.
- More sweat than usual.
- Tight and sore muscles.
- Increased anxiety, restlessness, and irritability.
- Difficulty concentrating because your brain is focused on survival.
For instance, if you’re crossing the street and a car comes speeding toward you, your body jumps back on its own before you’ve had a chance to think it through. This is the sympathetic state quickly kicking into action.
Additionally, trauma or anxiety can keep your sympathetic nervous system fired up for long periods even when there’s no real danger.
Dorsal Vagal State: Freeze, Shutdown, and Collapse
The dorsal state is the least talked about among the three autonomic nervous system states. It happens when your body produces a shutdown in response to a threat because it believes fighting or running away won’t work.
People in this state experience:
- Feeling emotionally disconnected from those around them.
- Extreme tiredness.
- Difficulty thinking clearly.
- Feeling detached from reality.
- Wanting to withdraw from people.
- Feeling unable to act.
- Nausea.
The shutdown response is NOT a lack of motivation. According to the polyvagal theory, it’s a survival strategy that the nervous system uses when it believes there are no other options.
Research also says that when the dorsal vagal state stays triggered for too long, it can contribute to gastric ulcers or irritable bowel syndrome.[4]
Understanding Safety Cues and Neuroception
“Neuroception” is a term Dr. Stephen Porges coined to describe how your neural circuits determine whether a situation is safe or unsafe.[5]
It is an automatic process that happens without your conscious thought, similar to how your eyes adjust to a dark room without you deciding to make it happen.
Neuroception happens in the primitive parts of the brain. It uses the tone of voice, facial expression, eye contact, posture, the pace of someone’s speech, and so on to make a quick decision about the safety of the situation.
Cues of safety allow your brain to stay calm and make a healthy human connection. These cues include:
- A gentle tone of voice.
- A familiar face.
- Warm facial expressions.
- Steady eye contact.
- Being in a comfortable environment.
However, some cues trigger a defense response; they are known as danger cues, and include:
- Someone yelling at you.
- Angry facial expressions.
- Sudden loud noises.
- Conflict.
- Uncertainty.
- Situations that remind you of past stressful experiences.
When safety cues are present, your body is more likely to enter the ventral vagal state. But in the presence of danger cues, you are likely to experience a sympathetic or a dorsal vagal state.
The response to cues – neuroception – is very personal. Two people can experience the same cues but react very differently to them because their nervous systems interpret safety and danger based on their past experiences.
For example, one person might enjoy speaking in front of a crowd. But another’s nervous system might immediately respond to being in front of a crowd with anxiety because it associates public speaking with embarrassment.
What Is the Window of Tolerance?
The window of tolerance was introduced by psychiatrist Dan Siegel in 1999. It is the range of emotional and physical arousal in which you are able to function at your best.[6]
The concept of the window of tolerance is not a part of polyvagal theory, but it ties into the nervous system’s response to stress.
When you are within your window of tolerance, your nervous system is balanced enough for you to manage everyday challenges without becoming overwhelmed. It is when you can:
- Think clearly.
- Regulate your emotions.
- Solve problems.
- Respond to requests at work.
If the stress you experience gets too intense, you are above your window of tolerance, which is called “hyperarousal.” It is very similar to the sympathetic, fight-or-flight, state of polyvagal theory. And if you find yourself in a situation from which escape is difficult, you get below your window of tolerance, which is called “hypoarousal,” similar to the dorsal vagal shutdown state.
The size of each person’s window of tolerance is different.
Factors that narrow your window of arousal are:
- Chronic stress.
- Trauma.
- Poor sleep.
- Illness.
- Life stressors.
On the other hand, healthy relationships, regular physical activity, mindfulness, quality sleep, and therapy can widen your window over time.
Mission Connection is here to help you or your loved one take the next steps towards an improved mental well-being.
Link Between Polyvagal Theory and Trauma
Trauma causes nervous system dysregulation in that it can keep you swinging between sympathetic overdrive and dorsal vagal shutdown only, and not the ventral state. So people with a trauma history may live much of their life bouncing between feeling anxious and feeling numb.
Normally, one overwhelming event will shift the brain into producing either a fight-or-flight response or a freeze response. Once the danger passes, the nervous system will return to a regulated state.
However, after traumatic experiences, the brain continues to behave as if the threat is still present. It is more sensitive to danger cues and less responsive to safety cues. In other words, neuroception, which is the body’s internal safety detector, becomes dysfunctional because it interprets harmless situations as threatening too.
This explains why trauma survivors describe that their reactions feel disconnected from logic, where a certain smell or tone of voice can trigger a full stress response.
Signs of Nervous System Dysregulation
Whenever you are outside your window of tolerance, your nervous system is dysregulated.
Nervous system dysregulation does not necessarily mean that something is “wrong” in the way your brain works. It is rather that the body’s stress response is having trouble recognizing when it is safe to relax.
The signs of dysregulation can be hyperarousal or hypoarousal.
Signs of Sympathetic Activation:
- Rapid, shallow breathing
- Visible muscle tension
- Sweaty palms
- Racing thoughts
- Increased reactivity to anger
- An exaggerated startle response
- Trouble sleeping
- Irritability
Signs of Dorsal Vagal Shutdown:
- Low, shallow breathing
- Flat facial experssion (also sometimes described as “frozen” appearance)
- Difficulty thinking
- Emotional numbness
- Reduced awareness of your surroundings
- Brain fog
- A strong pull to isolate yourself
- Low motivation
Aside from these signs, people can have physical symptoms in their bodies, like:
- Chronic fatigue.
- Headaches.
- Indigestion.
- Constipation.
- Irritable bowel syndrome.
Can You Improve Your Vagal Tone?
Vagal tone means how well your vagus nerve regulates your body’s rest and digest functions. But is it possible to improve it?
In medical research, vagal tone is estimated using heart rate variability (HRV), which measures the variation in time between heartbeats. Higher HRV is considered a sign of stronger vagal activity.[7]
There is, unfortunately, no single hack that instantly improves your vagal tone.
However, regular moderate aerobic activity has been shown to improve HRV in both healthy people and those with chronic illnesses.[8] Additionally, slow, controlled breathing (five to six breaths per minute) can also increase vagally mediated HRV temporarily.[9]
Other habits that increase your vagal tone over time include:
- Getting enough sleep.
- Maintaining supportive social relationships.
- Practicing mindfulness.
- Managing chronic stress.
The evidence that cold showers can improve vagal tone is limited; more research is needed before it can be recommended as a reliable method to improve vagal tone.
Find Mental Health Support at Mission Connection
The polyvagal theory can help you make sense of why you react the way you do during difficult life experiences. Many of these responses are automatic survival mechanisms that you can change to achieve a stable ventral vagal state.
At Mission Connection, our licensed mental health professionals go beyond traditional treatment and provide life-changing care. Every patient’s treatment plan consists of evidence-based therapies to help them better understand their nervous system. If you regularly deal with anxiety, trauma, depression, chronic stress, or other mental health concerns, we will make you a tailored treatment plan based on proven therapeutic approaches.
We offer flexible outpatient treatment options, including both in-person and virtual therapy, and a hybrid approach. We also work with most major insurance plans, and our team can help you understand your coverage for mental health treatment.
Reach out to us online or call us at 866-833-1822 to find out how we can support your long-term recovery. Our compassionate team is available 24/7 to answer your questions and provide guidance with no obligation.
