Why Your Body Reacts Before Your Mind: Understanding Polyvagal Theory

I used to think my reactions were just emotional. A raised voice made me go silent. A certain look could shut my whole system down. Some days I could hold space for other people’s pain, and other days, even a kind question made me want to disappear.

It wasn’t until I learned about the nervous system that things began to make sense. Not just emotionally, but biologically. Because it’s not all in your head. It’s in your body. And your body is paying attention, even when you aren’t.

Polyvagal Theory changed how I understand that. Developed by Dr Stephen Porges, it explains how our autonomic nervous system responds not just to real danger, but to cues of safety or threat, often before our conscious mind has had a chance to process them. Your body is scanning your surroundings all the time. This process is called neuroception. It’s different from perception, because it happens without conscious awareness. Neuroception answers one question, over and over again: am I safe? That one question governs everything from how open you are in conversation to how well you sleep at night. It doesn’t wait for facts or logic. It reacts to tone, body language, facial expressions, even silence.

When the answer is yes, when your system detects safety, you remain in a state called ventral vagal. In that state, you’re grounded, calm, and socially engaged. You can think clearly. You can make eye contact. You can listen, empathise, and reflect. Your body feels soft. Your breath is steady. You don’t feel the need to run or defend yourself or explain things that don’t need explaining. You can be fully present with another person, or with yourself, without feeling the urge to shrink, flee, or fix. You feel like yourself.

But when the nervous system senses that something is off, and it only takes a slight shift, things begin to change. Your body moves into the sympathetic branch of the autonomic nervous system. This is fight or flight. Your heart rate increases. Your breath becomes shallow. You feel tight in your chest or throat. You might get defensive. Your tone sharpens. You’re flooded with adrenaline. Your thoughts race. This is not necessarily a bad thing. It’s designed to keep you safe in actual danger. The problem is, the same system that helped your ancestors run from tigers is now reacting to unread messages, complicated conversations, and unpredictable people.

If things continue to escalate, or if the nervous system perceives the threat as overwhelming and inescapable, you drop even further. Into shutdown. This is the dorsal vagal response. Your system doesn’t fight or flee anymore. It goes numb. You dissociate. You feel far away. You lose your words. You can’t cry. You can’t think. It’s like someone’s unplugged you. You’re still there, but not fully. Time slows down. You feel disconnected from your body, your emotions, or even reality. It can look like calm on the outside, but inside, it feels like absence.

And here’s the hardest part: this all happens automatically. You don’t choose it. You can’t just stop it with willpower. You don’t even always know it’s happening until you’re halfway through it. That’s because the nervous system is faster than thought. It’s supposed to be. It’s trying to keep you alive.

When I first learnt all of this, I saw my entire relational history differently. I looked at past arguments and thought, of course I froze. Of course I shut down. Of course I couldn’t find the words. I wasn’t being avoidant or immature. My body didn’t feel safe. And it wasn’t being dramatic. It was being efficient. It was protecting me.

That realisation changed everything.

Because once you understand that your body is responding to safety rather than logic, you start to become curious. You start asking new questions. What made me feel unsafe just then? Was it a tone? A look? A memory? A posture? Did it even have anything to do with this moment? Or did it remind me of something I didn’t know I was still carrying?

You begin to notice the gap between who you are in regulated moments and who you become when your system feels threatened. That gap can be huge. It can make you feel like a different person. You might be warm and articulate one day, and withdrawn and anxious the next. Not because your personality has changed, but because your nervous system has.

And that’s where the real work begins.

You can’t force regulation. You can’t shame yourself into feeling safe. You can’t muscle your way through a shutdown. That’s like yelling at a toddler to stop crying and expecting it to work. The nervous system doesn’t respond to control. It responds to safety.

So the question becomes: what makes me feel safe?

That question will have a different answer for everyone. For some, it’s the presence of a calm, grounded person. For others, it’s time in nature, rhythmic movement, or rituals of care. It might be the sound of your own breath, or a room with soft light. It might be gentle music, or a familiar routine. It might be being alone. It might be being held. You won’t know until you start paying attention. The body remembers. But it also reveals.

This is why things like co-regulation matter so deeply. We regulate better when we’re with people who are regulated themselves. Someone’s voice, posture, and presence can signal to your nervous system that it’s safe to come home. And this isn’t just emotional. It’s neurological. When someone speaks to you softly, holds eye contact, or remains grounded while you’re dysregulated, it activates the social engagement system. This is the same system that Porges identified as part of the ventral vagal state. It helps calm your heart rate, regulate your breath, and bring your thoughts back into coherence.

This is also why traditional talk therapy isn’t always enough. If you’re talking about trauma while your nervous system is in a fight or flight state, you might be reinforcing the pattern instead of resolving it. You might leave therapy feeling worse, not better. Because the words can’t land until the body feels safe enough to receive them.

That’s where somatic approaches come in. Modalities like Somatic Experiencing, EMDR, Internal Family Systems, or sensorimotor psychotherapy all work with the body, not just the mind. They help you track sensation, notice activation, and come back into the present moment gently. They don’t rush. They don’t analyse. They honour the pace of the nervous system.

And then there’s daily life. Healing doesn’t just happen in a therapy session. It happens in a thousand small moments. When you notice you’re starting to shut down and you take a slow breath instead of powering through. When you excuse yourself from a conversation before it overwhelms you. When you say, I need a minute. When you rock gently in a chair and feel your feet on the floor. When you hum. When you rest your hand on your chest and remind yourself you’re still here.

These moments matter more than you think. Because every time your nervous system experiences safety, even for a few seconds, it rewires. That’s the gift of neuroplasticity. The brain can learn new patterns. The body can unlearn fear. Not all at once. Not perfectly. But gradually, over time. It’s not about erasing the past. It’s about giving the present enough safety that the past no longer runs the show.

This work is not linear. Some days you’ll feel like you’re making progress. Other days, you’ll be back in a spiral you thought you’d outgrown. That doesn’t mean you’re failing. It means your nervous system is still learning. It means your body is still protecting you. It means you’re human.

And here’s the thing. Even knowing all of this, you’ll still get dysregulated. You’ll still shut down sometimes. You’ll still feel overwhelmed. But now, you’ll know what’s happening. You’ll have language for it. And that alone changes the experience. It creates a tiny space between the feeling and the story. Between the reaction and the meaning you make of it. That space is the beginning of compassion.

Because if you know your system is trying to protect you, it becomes easier to respond with care rather than criticism. You stop asking, what’s wrong with me? And start asking, what do I need right now? That question is the beginning of everything. It invites healing instead of hiding. It invites regulation instead of reactivity.

So when you find yourself overwhelmed, or numb, or ready to disappear, stop. Notice what’s happening. Put your hand on your chest. Breathe. Remind your body that it’s not in danger. That there’s no tiger in the room. That you’re here. And you’re safe.

Even if you don’t believe it yet, your nervous system is listening. And slowly, it will learn to trust you again.

That is the work. Not to never be dysregulated. But to come back. With softness. With patience. With love.

Further Reading and Resources

1. Porges, S.W. (2009). The Polyvagal Theory: New insights into adaptive reactions of the autonomic nervous system. Cleveland Clinic Journal of Medicine, 76(Suppl 2), S86–S90.

2. Porges, S.W. (2017). The Pocket Guide to the Polyvagal Theory: The Transformative Power of Feeling Safe. W.W. Norton.

3. Dana, D. (2018). The Polyvagal Theory in Therapy: Engaging the Rhythm of Regulation. W.W. Norton & Company.

4. van der Kolk, B. (2015). The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Penguin.