My Nervous System Is Not Broken. It's Just Running at Full Resolution
What neuroscience says about sensory overwhelm, hypervigilance, and why breathwork and psychedelics make biological sense
People say: go out with friends, have fun, socialize — and they say it like it's obvious. Like of course that would make you feel better. Energized. Happy.
And here's the thing: I do get happy to see my friends. Genuinely happy. But energized? No. Because when I go out there are noises, and the lights are bright, and so many things happen so fast that my nervous system gets overwhelmed before the evening has really even started. And then I spend the rest of the night managing that, instead of just being there.
This is what it's like to be neurodivergent. Not only on the autism spectrum, but also ADHD, and gifted — which in combination means, in plain terms, that my nervous system is very open. It does not filter sensory input with the same degree that neurotypical systems do.
Think of it like a measuring instrument. Some instruments measure in meters. Others in centimeters. Some in millimeters, or even finer. My instrument measures the world in very fine grain. I notice everything — the hum of the fluorescent light, the texture of the chair, the three conversations happening simultaneously at the next table, the slight shift in someone's tone of voice. All of it, all at once, at full resolution.
That's not a flaw. Sometimes it's extraordinary. But it comes at a cost.
What the body learns to do with that
Any nervous system, when it's running at that level of sensitivity, learns to protect itself. Because if you reach the end of your tolerance threshold — if the input keeps coming and there's no relief — you get overwhelmed, anxious, and you either freeze or have a meltdown. Neither of those is something you want in public. Neither of those is something you want in front of people you love.
So the nervous system finds its own solutions. Two of the most common ones, and the ones I know well: avoidance and hypervigilance.
Avoidance means not going to certain places. Leaving early. Saying no before the situation can become a problem.
Hypervigilance means constantly scanning ahead — planning carefully, assessing every context before entering it, calculating whether the sensory environment will be "safe" or "threatening." Will it be too loud? Too bright? Too unpredictable? Is there an exit I can use? Can I control enough variables to stay within my window?
It is exhausting. And it is constant.
And obviously — this is where I spent most of my life — the anxiety that comes with this is not a psychological problem that exists separately from the body. It is a direct result of what is happening physiologically. A 2025 study found that across a sample of 492 autistic and ADHD adults, auditory hyperreactivity was markedly elevated in both groups compared to neurotypical people — with large effect sizes — and that hypervigilance, hyper-focus, and inattention were all directly linked to sensory overreactivity, which in turn fed anxiety, which fed back into more hypervigilance. A self-sustaining loop, measurable and documented.
What's actually happening in the nervous system
This is where I want to pause and be specific, because understanding this changed everything for me.
The autonomic nervous system is the system that governs the involuntary functions of the body — heart rate, blood pressure, digestion, how alert or calm you feel at rest. It has two branches. The sympathetic branch is the gas pedal — it activates the body for action, threat, urgency. The parasympathetic branch is the brake — it promotes rest, recovery, digestion, and the ability to feel safe.
In a well-regulated nervous system, these two branches coordinate fluidly. The gas pedal fires when needed, the brake re-engages when the threat has passed. The system is flexible, context-sensitive, alive to the moment.
A 2021 clinical study found that autistic people had significantly elevated resting heart rates — 77 beats per minute on average compared to 63 in neurotypical controls, while lying down doing nothing. When standing up, the heart rate increase was also significantly larger in the autistic group. And when tested for the ability to constrict blood vessels under physical and mental stress, the autistic group showed significantly blunted responses — the brake was not engaging as it should.
A 2026 computational study took this further, building a mathematical model of autonomic regulation and feeding in real heart rate and blood pressure data from autistic and neurotypical individuals. Their finding: neurotypical nervous systems show clearly differentiated coordination patterns between the two branches depending on context. In the autistic nervous systems the sympathetic and parasympathetic nervous systems failed to cleanly separate when they needed to. The system could not switch gears. The brake and the gas pedal were both partially engaged simultaneously, regardless of what the situation called for.
In plain terms: the autonomic nervous system in neurodivergent people runs functionally differently — with the gas pedal higher at baseline, and the brake less able to engage and disengage flexibly in response to context.
The intuition the body had before the science caught up
Here's what I find remarkable, looking back. Long before I understood any of this, my body was already looking for the answer.
Just like someone with ADHD instinctively reaches for sugar and caffeine — not because they're weak-willed but because their system is low on dopamine and they're trying to self-regulate — I was instinctively drawn to meditation, breathwork, body-oriented practices, and eventually psychedelics.
I didn't have the language for it at the time. But I knew something: whatever needed to shift needed to shift at the level of the body. Not through understanding it better, not through thinking harder about it, not through more planning and managing and optimizing. Through something that could reach into the physiology itself and create the relaxation that my nervous system could not generate on its own.
Because constantly being "on" — constantly at that level of activation — doesn't just feel tiring. It feels painful. And I needed a way through.
What the science now says about breathwork and psychedelics
What I was doing intuitively turns out to have a coherent biological logic.
The computational study mentioned before found something practically significant buried in their modeling work: that deep, slow breathing — at around 9 breaths per minute — significantly enhanced the parasympathetic system's ability to lower elevated blood pressure, particularly under conditions of high sympathetic activity.
Normal breathing barely moved the needle. Deep breathing did.
The mechanism they propose is that slow, deep breathing repeatedly pushes the baroreflex — the body's blood pressure regulation system — into its most responsive range, amplifying the parasympathetic signal in a way that shallow or normal breathing simply does not.
The body has a lever, and slow breathing is how you pull it.
But how about psychedelics? A 2025 viewpoint paper, synthesizes the emerging evidence. Psychedelics — primarily psilocybin, LSD, and DMT — act through serotonin receptors that are distributed not just in the brain but throughout the peripheral nervous system, including the heart, lungs, and gastrointestinal tract. This means their effects reach into the autonomic system directly, not just through psychological experience.
Let's start with what the research actually found in the body.
Psilocybin — the active substance in magic truffles — has been found to strengthen vagal tone. Remember the brake we talked about? Vagal tone is essentially how strong and responsive that brake is. The stronger it is, the better your system can shift out of high alert and into rest. Psilocybin appears to make that brake more functional.
Ayahuasca — a traditional brew containing DMT — has been shown to increase heart rate variability. This is the measure we use to assess how flexibly the nervous system can move between states. Higher heart rate variability means the system is less rigid, more able to respond to what's actually happening rather than staying stuck in one mode.
Both of those are measurable, physiological changes.
Not just "people felt better."
The body changed.
Then there's what happens in the brain. Psychedelics reduce activity in the amygdala — the brain's alarm centre, and the structure most implicated in hypervigilance. At the same time, they strengthen the connection between the amygdala and the prefrontal cortex — the part of the brain that is supposed to be able to say "we're safe, stand down." What the researchers propose is this: during a psychedelic experience, the sympathetic system initially activates — the body goes into a kind of heightened state. But then, as the experience unfolds, the parasympathetic system rebounds. The brake surges back.
And the suggestion is that this swing — this full range of motion through the autonomic system — may be part of what creates the recalibration. Or a restet if you like. And not just in the moment, but afterward also.
Can I relate to this? Yes. Is this completely understood? No. The evidence base here is promising but still early, and the sample sizes in psychedelic research remain small. We do not yet have a complete mechanistic picture of exactly how durable these autonomic shifts are, or what determines whether they last.
Still, the biological logic is coherent, the early findings are consistent, and they align precisely with what the neuroscience of dysregulation has shown about what needs to shift.
This is not a one-time fix
I want to be clear about something, because the way psychedelics are sometimes discussed makes it sound like one profound experience and everything is different.
That's not how I think about it, and it's not how I work with it.
Shifting physiological dysregulation that has been building for a lifetime — that has functional correlates in how your nervous system is organized, in autonomic baseline, in the body's chronic inflammatory and stress hormone patterns — is not a one-time job. It is a practice. A constant, daily recalibration, supported by more intensive work at intervals.
The daily practice is the breathwork, the movement, the body-oriented approaches — the things that keep the window of tolerance open, that give the parasympathetic system regular practice at being activated. The bigger doses — the ceremonial work, the intensive retreat contexts — are the moments of deeper reset, where something more fundamental gets the opportunity to shift.
Each supports the other. The daily practice makes you more able to work with the depth of the ceremonial experience. The ceremonial experience gives the daily practice something more to consolidate.
Why this led us to Hearts Door
This is the understanding that shapes everything we do at Hearts Door Retreats.
We don't offer a psychedelic experience as a standalone event. We offer a container — preparation, the work itself, integration afterward — because we understand that the body needs more than a single powerful moment. It needs the context to make meaning of what happened, and it needs practices to bring the shifts into daily life.
In our retreats, we work with breathwork and body-oriented practices alongside truffle ceremony — not as add-ons, but as the core of what creates the conditions for the nervous system to actually do something it rarely gets to do: exhale. Fully. Without immediately scanning for the next threat.
People leave feeling released. Relaxed in a way that isn't just about mood, but about something deeper — like the body has been given permission to stop bracing. Like the measuring instrument that never turns off has, for once, been allowed to rest.
That's what we're working toward. Not a cure. Not a solution. A practice, a direction, a way of working with the nervous system rather than against it.
For those of us who have spent a lifetime being told to just go out and have fun — that might be the most radical thing of all.
Post by co-founder Ioana
At The Heart's Door, we work with psilocybin in ceremonial contexts and support structured integration practices. Curious about our retreats combining psilocybin, breathwork and body-oriented practices? Read about our work here
