Polyvagal Theory and The Highly Sensitive Nervous System (with Justin Sunseri)

Do you ever feel overwhelmed and confused by the unending conveyor belt of new labels, healing methods, and training programmes, all professing to be the missing piece in the puzzle of your life? Is the polyvagal theory another one?

We are often sold the latest systems and interventions requiring expert knowledge. We throw our money at solutions with no fixed destination and a never-ending supply of potential new up-sells and add-ons. It is easy to get caught in personal development cycles, constantly seeking the next thing that promises to help us get unstuck.

But rather than being stuck because we have not found the perfect model, what if the very quest for perfect itself is a symptom of being stuck at a deeper, more foundational physiological level?

In a recent episode of The Gentle Rebel Podcast, therapist and podcast host, Justin Sunseri joined me. Justin shares his passion for Polyvagal Theory and its transformative role in trauma recovery and emotional regulation. In this post, I’ll share key ideas from our conversation and how they might resonate with those of us who are highly sensitive.

Polyvagal Theory: The Science of Safety

Justin describes Polyvagal Theory as the “science of safety”. Developed by Dr Stephen Porges, it explains how mammals – including humans – respond to danger, safety, and connection through the autonomic nervous system.

Rather than seeing ourselves as broken or defective, Polyvagal Theory invites us to understand that when we feel stuck or disconnected, it is not because we are failing. It is because our nervous system is caught in a defensive state, such as fight, flight, shutdown, or freeze.

These states are biological survival responses, not character flaws. They have served important functions in keeping us safe in the past, but they can also become habitual when the body no longer recognises when it is safe to relax.

This framework offers a powerful alternative to self-blame and shame. Instead of asking “What is wrong with me?”, we can ask “What happened to my system that it adapted this way?”

Justin’s Journey Into Polyvagal Theory

Justin discovered Polyvagal Theory during his time as a frustrated therapist working in high-needs U.S. school districts. Despite his best efforts, he often struggled to help students deeply impacted by trauma. Traditional therapeutic approaches were falling short.

During a summer break devoted to research, he stumbled upon Polyvagal Theory. Initially sceptical, Justin realised it explained the underlying science behind trauma responses he was witnessing. It linked the biological processes of the body (studied by Porges) with practical somatic techniques (pioneered by people like Peter Levine).

It clicked: his clients were not consciously choosing their behaviours. Their bodies were reacting automatically to real or perceived threats.

How We Get Stuck

According to Polyvagal Theory, our nervous system moves between three core states:

• Ventral Vagal (Safety and Social Connection): where we feel calm, connected, creative, and compassionate.
• Sympathetic (Fight or Flight): where we feel mobilised, anxious, irritable, or aggressive.
• Dorsal Vagal (Shutdown and Freeze): where we feel disconnected, numb, hopeless, or collapsed.

Highly sensitive people may be especially attuned to these shifts, but may also find themselves overwhelmed by chronic stuckness in defensive states.

Justin emphasised that when we are stuck, it is not about willpower or mindset. It is a biological process. Real healing involves gradually climbing back up the “Polyvagal Ladder” towards safety – not forcing ourselves to think positively, but restoring the body’s capacity to feel safe.

Polyvagal Theory – Mixed States and New Developments

We also discussed the concept of mixed states — combinations of primary nervous system reactions:

• Play: A healthy mix of mobilisation (fight/flight) and safety.
• Stillness: A healthy mix of shutdown and safety (e.g., calm presence without fear).
• Freeze: A defensive mixture of shutdown and sympathetic activation (e.g., tense immobility).

Justin also shared his concerns about newly proposed mixed states like appeasement, fawning, and intimacy being introduced without strong scientific backing. While these terms might be descriptively helpful, he cautioned against the confusion that endless layering of models and metaphors can bring.

The Trap of Endless Models

One of the highlights of our conversation was Justin’s story about inventing “Puzzle Completion Therapy” — a completely fictional therapeutic model based on the idea that people have missing puzzle pieces inside them. It sounded plausible, but it was made up.

The point was clear: it is dangerously easy to create legitimate-sounding frameworks that keep people hooked into endless self-improvement journeys. And many people, especially those who are highly sensitive and searching for meaning, can find themselves trapped in these cycles.

Rather than searching for the “perfect” model, the real invitation is to come home to ourselves – to notice, with compassion, what our bodies are feeling, and to engage with our own nervous systems directly.

Therapy, Coaching, and Red Flags

Justin spoke about the importance of viewing therapy and coaching as temporary resources, not lifelong dependencies. A good practitioner should equip you with tools for self-regulation, rather than requiring ongoing allegiance.

Red flags to watch out for include:

• Professionals who create complex systems only they can interpret.
• Programmes that constantly upsell additional certifications or steps.
• Dependence on metaphors or parts models that create distance from your actual bodily experiences.

Ultimately, the goal is empowerment: learning to regulate your own nervous system and reconnect with your inner safety, without becoming reliant on external structures or authorities.

Find Out More About Justin and The Polyvagal Theory

If you want to explore Justin’s work further, his website justinlmft.com is the hub for his podcasts, courses, and resources.