Understanding Polyvagal Theory: Why Nervous System Flexibility Matters
- Katie Carhart, PhD
- 5 hours ago
- 4 min read
Polyvagal theory offers a powerful framework for understanding how our nervous systems respond to safety, stress, and threat. Rather than viewing anxiety, shutdown, or irritability as personal shortcomings, this approach helps us understand these reactions as adaptive nervous system responses shaped by experience, context, and history (such as trauma).
At its core, polyvagal theory reminds us that the nervous system is always working to protect us. The goal of nervous system regulation is not to stay calm all the time: it is to build flexibility: the ability to move between states and return to safety and connection when possible.
A Brief Overview of Polyvagal Theory
Polyvagal theory describes three primary nervous system states:
Ventral vagal (regulation and safety): a state of connection, presence, and engagement.
Sympathetic activation (fight, flight, fawn): mobilization for action when threat is perceived.
Dorsal vagal shutdown (freeze): immobilization and withdrawal when action feels impossible.
We move in and out of these states throughout the day. This movement is normal and necessary. Problems tend to arise when stress, trauma, or chronic overwhelm reduce our ability to move flexibly between states.
When Nervous System Flexibility Is Limited
When the nervous system becomes stuck in activation or shutdown, our ability to function can be impacted in meaningful ways.
Sympathetic Activation in Daily Life
In sympathetic states (fight, flight, or fawn), the body is oriented toward survival rather than connection. This can show up as:
Snapping at a partner or children
Feeling easily overwhelmed or irritable
Reacting strongly to minor stressors
Restlessness, anxiety, or urgency
Difficulty slowing down or thinking clearly
These reactions are not character flaws, they are signals of nervous system activation.
Why Awareness Makes a Difference
One of the most effective ways to support nervous system regulation is through early awareness.
When we notice the first signs of activation, such as muscle tension, shallow breathing, racing thoughts, or a sense of urgency, we have more options. Awareness creates space to pause, respond intentionally, and choose regulation strategies before reactions escalate.
Even if we do move fully into a stress state, recognizing it sooner can reduce shame and increase compassion. Instead of asking “What’s wrong with me?” we can shift to “My nervous system is activated right now: what might help?”
Regulation Is About Recovery, Not Perfection
Being regulated does not mean never getting dysregulated. It means:
Noticing stress sooner
Recovering more quickly
Having tools that support regulation
Repairing after moments of disconnection
This ability to move between states and return to safety is often described as the window of tolerance. Expanding this window takes time, practice, and support, especially for those with a history of trauma or chronic stress.
Nervous System Capacity Matters
Polyvagal theory also helps us understand why change can feel difficult at times.
When someone is in a dorsal vagal (freeze or shutdown) state, the nervous system may not have the capacity to take in new information, try new skills, or make decisions. In those moments, offering strategies or solutions often doesn’t land, not because someone isn’t trying, but because their system is prioritizing survival.
Understanding nervous system capacity allows for a more compassionate and effective approach to healing.
Working With Your Nervous System, Not Against It
Polyvagal theory invites a different question:
What does my nervous system need right now?
Sometimes the answer is movement or action. Sometimes it’s rest, connection, or simply noticing what’s happening in the body. Healing and regulation happen most effectively when we work with the nervous system rather than pushing past its limits.
Limits of Polyvagal Theory
It’s also important to note that Polyvagal Theory includes a mix of well-established autonomic physiology and theoretical elements that continue to be debated in the scientific literature. Some of the theory’s specific anatomical and evolutionary explanations are not fully supported by empirical research and remain controversial. Acknowledging this matters. At the same time, the clinical usefulness of the framework does not depend on every proposed mechanism being confirmed. As a whole, polyvagal-informed work offers a practical way to understand nervous system states, capacity, and stress responses, helping clinicians and clients alike recognize when regulation, pacing, or support is needed before change or skill-building can occur.
How Polyvagal Theory Informs Therapy
Polyvagal theory has important implications for therapy, particularly in understanding nervous system capacity. When clients are in states of high activation or shutdown, their ability to process information, reflect, or try new skills may be limited. For example, when someone is in a dorsal vagal (freeze) state, offering new coping strategies or tools is often not helpful, not because the client is resistant or unmotivated, but because their nervous system does not yet have the capacity to take in or apply new information. Noticing which state a client is in allows therapy to meet them where they are, prioritizing safety and regulation first, rather than pushing for change before the system is ready. When capacity increases, learning and skill-building can follow more effectively.
Interested in Working Together?
I integrate polyvagal-informed, trauma-informed approaches into therapy to support nervous system regulation, emotional awareness, and sustainable change. Together, we focus on building flexibility, expanding the window of tolerance, and responding to stress in ways that feel supportive rather than overwhelming.
If you’re curious about how this approach might support you, you can learn more about working with me here or reach out to schedule a consultation.
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