Notes on The Nervous System

There is a moment that most people recognise, even if they have never had language for it. You are in the middle of an ordinary day — a meeting, a conversation, a quiet Tuesday afternoon — and something shifts. The air feels slightly thinner. Your thoughts become faster and less coherent. A familiar tightness arrives in the chest or the throat. You are not in danger. Nothing has objectively changed. And yet your body is behaving as though something has.

This is your nervous system doing what nervous systems do. And understanding it — really understanding it, not just knowing that stress exists — is one of the most practically useful things you can do for your mental health, your relationships, your physical health and your capacity to live the life you actually want.

This is what I want to talk about today.

The System Beneath the System

Your nervous system is the biological infrastructure through which every experience of your life occurs. Every sensation, every emotion, every thought, every movement. It is the medium through which you perceive the world and through which you respond to it. And most of it operates far beneath the level of conscious awareness — running automatically, continuously, adjusting and responding and assessing without any input from you at all.

The part of the nervous system that matters most for daily wellbeing is a subdivision called the autonomic nervous system. It governs the involuntary functions — heart rate, breathing depth and rate, digestion, immune activation, hormone release. And at its core, it is doing one thing, constantly, that shapes your experience of being alive more profoundly than almost anything else: it is assessing whether you are safe.

Not consciously. Not deliberately. It is not a thought process or a decision. It is a continuous, automatic, biological appraisal of your environment, your body, your relationships and your history — and based on that appraisal, it is selecting a state. A state that then colours everything: how you think, what you feel, how you relate to others, what actions feel possible and what feels entirely out of reach.

Dr. Stephen Porges, the neuroscientist whose polyvagal theory has quietly revolutionised our understanding of the autonomic nervous system, calls this process neuroception — the nervous system's constant below-conscious scanning for cues of safety or danger. We do not choose our neuroceptive responses any more than we choose our heart rate. They arise from the body's assessment of the current moment, filtered through every moment that came before it.

Three States, Not Two

For most of the 20th century, the autonomic nervous system was understood as having two modes: the sympathetic (fight-or-flight, activation, stress) and the parasympathetic (rest-and-digest, calm, recovery). On or off. Accelerator or brake. This was the model taught in medical schools, used to explain anxiety and stress responses, and broadly accepted as an accurate description of how the system worked.

Polyvagal theory complicates and significantly enriches this picture. What Porges's research revealed is that the autonomic nervous system operates not through two states but through three — and that these three states are hierarchical, each with a distinct biological profile, a different quality of inner experience, and different capacities available within it.

The first and most recently evolved state is what Porges calls the ventral vagal state — the state of safety and social engagement. When your nervous system is in ventral vagal, you are genuinely calm without being flat. Curious without being anxious. Open to connection without feeling threatened by it. The prefrontal cortex is fully online. You can think clearly, feel emotions without being overwhelmed, access creativity and hold complexity. This is not a rarefied or exceptional state — it is your biological home, the state you were designed to inhabit as your default. It is the state from which genuine living happens.

The second state is the sympathetic state — fight or flight, mobilisation for perceived threat. Heart rate elevated, breathing faster and shallower, muscles tense, thoughts rapid and often catastrophic. This state exists on a spectrum from productive activation and focused energy at its milder end, through irritability and anxiety, to full panic at its most intense. Here is the thing that I find most important about the sympathetic state: most people in the modern world are living in mild-to-moderate sympathetic activation as their baseline, without fully recognising it as such. The rushing, the striving, the difficulty switching off, the low-grade restlessness that never quite resolves — this is the sympathetic nervous system running quietly in the background, treating ordinary daily life as a series of demands that require mobilisation.

The third and most ancient state is the dorsal vagal state — freeze, shutdown, collapse. This is the nervous system's last resort when both fight and flight have been assessed as impossible or insufficient in the face of overwhelming threat. Numbness. Disconnection. A heaviness that makes everything feel effortful. Flatness. The sense that nothing quite matters or is worth trying. Dorsal vagal is widely misunderstood because it does not always look like crisis. It can look like chronic low motivation. Like depression that does not respond to positive thinking. Like the particular exhaustion that sleep does not seem to fix. Like going through the motions of a life that used to feel meaningful.

Why This Map Changes Things

I discovered polyvagal theory properly — not as an intellectual concept but as a lived map — during a period when I was struggling to establish a daily meditation practice. I would sit down each morning with every intention, and within two or three minutes find myself flooded with a restlessness so physical that stillness felt genuinely impossible. I was frustrated with myself. I kept adding it to the list of things I could not seem to do despite wanting to.

Then I read Deb Dana's articulation of the polyvagal ladder, and something clicked into place: I was trying to use a ventral vagal practice from a sympathetic state. Meditation, in its stillness and its requirement for present-moment presence, is a ventral vagal practice. It is most accessible from ventral vagal. When you are in sympathetic activation — even mild activation — trying to immediately sit still and meditate is a bit like trying to take the stairs from the basement when you are standing on the ground floor. The stairs are real. They are right there. But you are not standing where you think you are.

The solution was not to try harder at meditating. It was to move first. Five minutes of gentle shaking. A short walk. Some humming while I made coffee. Physical movement that helped the nervous system discharge some of the sympathetic activation — so that by the time I sat down to breathe and be still, the stillness was actually accessible.

This sounds almost comically simple. But it worked, because it was neurologically correct. And that is the practical gift of this map: it tells you not just that you are struggling, but which direction to move from where you actually are.

The Path Back Is Not What You Think

Here is the insight from polyvagal theory that I find most important and most consistently overlooked, including by people who are deeply familiar with the theory: the path back to regulation always follows the hierarchy. Always. You cannot jump directly from shutdown to safety. You have to move through mobilisation first.

This means that if you are in a dorsal state — flat, numb, heavy, disconnected, unable to feel much of anything — the standard advice of 'take some deep breaths and meditate' will likely not work, and will possibly make things worse by adding frustration to the flatness. What works from dorsal is mobilisation: movement, warmth, sound, the presence of a safe other person. Anything that begins to reintroduce some activation. Once you have moved up the ladder into sympathetic territory — once there is some energy available, even if that energy feels anxious or restless — the downregulation practices become accessible. Breathwork. Mindfulness. Stillness. The practices that are genuinely wonderful from ventral vagal, but that require some degree of ventral vagal resourcing to access.

The sequence is: mobilise first, then regulate. Movement before meditation. Shaking before stillness. Sound before silence. Not always, not as a rigid rule, but as a general navigation principle based on where you are actually starting from.

The Vagus Nerve and Why It Matters

No notes on the nervous system would be complete without talking about the vagus nerve, because it is — I am increasingly convinced — the most important nerve in the body for everyday wellbeing, and the one most within our capacity to deliberately influence.

The vagus nerve runs from the brainstem through the neck, branches through the heart and lungs, passes through the diaphragm and extends down into the gut. It is the primary pathway of the parasympathetic system and the anatomical foundation of the polyvagal model. Its tone — the health, responsiveness and flexibility of the nerve itself — is one of the strongest biological predictors of emotional resilience, cardiovascular health, reduced inflammation and capacity for genuine connection that we have.

High vagal tone means the nervous system can move fluidly between states. It can activate when activation is needed and recover quickly when the demand passes. It can tolerate difficulty without collapsing and return to baseline without prolonged effort. It is, essentially, a measure of nervous system fitness. And like physical fitness, it responds to training. It builds through consistent practice. It degrades with chronic stress, isolation and neglect.

The practices that build vagal tone are not mysterious or difficult to access. Extended exhale breathing — in for four counts, out for six or eight — directly activates the vagal brake within seconds, shifting the body measurably toward parasympathetic dominance. Humming and singing vibrate the vagus nerve through the throat and larynx. Cold water on the face activates the dive reflex and the vagal brake simultaneously. Safe, warm social connection — being genuinely seen and met by another person — co-regulates the nervous system through the social engagement pathways that Porges identified as integral to vagal function. Time in nature. Movement. Laughter. Each of these, practised consistently, builds the nerve's responsiveness over time.

What strikes me about this list is how it maps almost perfectly onto what humans have always instinctively sought when distressed. We reach for connection. We go outside. We move. We make sound. We have always known, in the body, what the body needed. The neuroscience just gives us the precise biological explanation for why.

A Note on Dysregulation

One thing I want to say clearly, because I think it is important: nervous system dysregulation is not a character flaw. It is not evidence of weakness or insufficient resilience or a failure of personal development. It is an intelligent biological response to demands that have exceeded the system's current resources — and in many cases, it is the predictable outcome of a history that would have dysregulated any nervous system.

Many of us grew up in environments where the nervous system was chronically activated without adequate co-regulation. Where expressing distress was unsafe, or where the adults around us were themselves too dysregulated to provide the regulating environment a developing nervous system needs. The nervous system learned, very wisely, to manage on its own. To stay vigilant. To suppress. To perform okayness while something quite different was happening underneath.

That learning was not a failure. It was adaptation. The patterns that feel like problems now — the hypervigilance, the shutdown in the face of intensity, the difficulty tolerating uncertainty, the emotional flooding or emotional blunting — began as solutions. They were the best available responses to the specific conditions of a specific history.

Understanding them as nervous system responses rather than personality traits does something important: it moves the conversation from judgment to navigation. Not 'what is wrong with me' but 'where am I on the map, and which direction do I need to move from here.' This is not a small shift. In my experience, it is one of the most quietly transformative shifts available.

Tending to the System

The nervous system is not something that happens to you. Once you have the map — once you can recognise the three states, notice your own patterns of activation and shutdown, and understand which direction to move from wherever you are — it becomes something you can genuinely work with.

This does not require hours of daily practice. It does not require a perfect lifestyle or the elimination of stress or a specially designed environment. It requires, at its most fundamental level, two things: the capacity to notice where you are — which state you are in, which direction you are moving — and a small repertoire of practices that reliably help you navigate. A few minutes of breathwork. A short walk. A moment of genuine connection. Some humming in the shower that you no longer feel embarrassed about because now you know exactly what it is doing to your vagus nerve.

The nervous system is always trying to keep you safe. Even when its strategies are no longer helpful. Even when the vigilance is scanning for threats that are not there, or the shutdown is protecting against dangers that have long since passed. It is always doing what it learned to do in the conditions it learned to do it in.

The work of nervous system regulation is not fighting this. It is understanding it well enough to gently, consistently, over time, offer the system new evidence. Evidence that it is safe to settle. That the threat has passed. That rest is not dangerous. That connection is available. That the ventral vagal state — the home state, the state where genuine living happens — is not a luxury or an achievement but a biological birthright, available to anyone willing to do the patient, practical work of returning to it.

Again and again, imperfectly and faithfully. Until it begins, incrementally, to feel like home.