I want to start with a question. When did you last consciously unclench your jaw?
Not because something stressful was happening. Just when did you last notice it was tight, and let it go?
For a long time I didn’t notice mine at all. It would be tight for hours (the whole morning sometimes) and I’d only become aware of it when something made me consciously relax it. In that moment, I’d realise it had been clenched for I didn’t know how long. That wasn’t an occasional thing. That was my baseline.
I’m going to tell you what I’ve learned about why that happens. What’s actually going on in the body when the tension becomes the background rather than the foreground. Because I think it’s one of the most under-explained pieces of women’s health. And I think understanding it changes something, even when you can’t change the circumstances that cause it.
The stress that doesn’t have a name
The load I carry is, in many ways, one I chose. I homeschool two daughters. I work and study alongside that. My life doesn’t have a commute, or a handover, or a defined moment when I am clearly off duty. The boundary between thinking hard and being a present parent is extremely porous and often nonexistent.
What this produces is a particular quality of stress: not acute, not crisis-level, just a constant low level stress. The kind where nothing is specifically wrong, but the readiness or hypervigilance never quite leaves. The gut symptoms that are partly food but also something else. The reactivity to certain sounds, particularly my children bickering which lands in me harder than other noise, that feels out of proportion to the trigger.
And underlying all of it: a difficulty remembering the last time I’d felt genuinely, deeply at ease. Not just not-stressed, but actually relaxed.
I started looking into the nervous system research because I was seeing it become more widely discussed and I was curious whether it explained what I was experiencing. And suddenly I had language for something that had been happening in my body for years.
What the HPA axis is actually doing
The HPA axis (hypothalamic-pituitary-adrenal axis) is your body’s primary stress response system. Three structures working together. When something threatening happens, your hypothalamus signals the pituitary, which signals the adrenal glands to release cortisol. Cortisol mobilises energy, sharpens attention, prepares you to respond. When the threat resolves, a feedback loop tells the hypothalamus to stand down, cortisol drops, and the system returns to baseline.
That design works beautifully for the kind of stress humans evolved with: short duration, physical, and with clear resolution. It is not designed for the mental load that never empties. The financial concern that sits in the background. The responsibility for small people who need things constantly. The study deadline and the client case and the children’s argument, all at the same time.
When stressors are chronic and unresolved, the HPA axis doesn’t get the stand-down signal. Cortisol doesn’t return to baseline cleanly. And because cortisol is a circadian hormone (its peak in the morning and its decline through the day are part of the architecture of the body clock) a dysregulated HPA axis directly disrupts circadian rhythm. Which disrupts sleep. Which disrupts stress regulation. Which dysregulates the HPA axis further. This is not a metaphor. It’s one interconnected system, and each disruption compounds the others.
The concept of allostatic load is useful here. Allostasis is what the body does to maintain stability under demand; the active, effortful process of adapting. Allostatic load is the cumulative cost of sustained adaptation. The jaw that stays tight, the cortisol that never quite cleans up, the nervous system that has learned to stay ready.
I found this framework clarifying rather than alarming, because it removed a layer of self-blame from what I was experiencing. My nervous system wasn’t failing. It was doing exactly what nervous systems do under sustained demand: adapting, staying online, keeping the system running. The cost of that sustained readiness is what I was feeling.
The polyvagal piece — and why it matters
Polyvagal theory, developed by Stephen Porges, offers a more useful map of the nervous system than the simple stressed/not-stressed binary. It describes three states. The ventral vagal state, or the social engagement system, is where we feel safe, connected, regulated. Genuine rest lives here. The sympathetic state is mobilisation — the stress response. And the dorsal vagal state is shutdown — the freeze response, immobilised collapse under overwhelming threat.
Most women under chronic load oscillate between sympathetic and something approaching dorsal vagal, between activated and depleted, without much time in the ventral vagal state. The deeply relaxed, genuinely at ease feeling becomes unfamiliar not because anything is wrong with you, but because you’re rarely there.
The vagus nerve is the physical pathway of the ventral vagal state. Its tone (its health and responsiveness) determines how quickly you can shift back to regulation after activation. Low vagal tone means slower recovery, more reactivity, more difficulty accessing calm. Higher vagal tone means more resilience and faster return to baseline. And vagal tone can be trained.
What actually helps — and why
I want to share what I do — not as a protocol, but as things that genuinely work, with the research that explains why.
Morning sunlight is the foundation. I’ve talked about this in the circadian context across multiple episodes. What I want to add here is the nervous system layer. There’s a growing body of research on photobiomodulation, which is the biological effects of specific light wavelengths on cellular processes. Natural sunlight, particularly the near-infrared wavelengths present in morning and late afternoon light, appears to support mitochondrial function and has direct effects on inflammatory markers and nervous system regulation. Being in actual sunlight feels different from being in shade. The research helps explain why.
Grounding, or barefoot contact with the earth, is the practice I find most people dismiss until they try it consistently. The earth carries a mild negative charge. Direct skin contact allows free electrons to transfer into the body. Studies measuring cortisol rhythms, heart rate variability, and inflammatory markers show measurable changes from consistent grounding. When I’m in a state of overwhelm and can’t leave the house, I go into the garden with bare feet, and something shifts. Not immediately, but within a few minutes. The research gives me a mechanism for something I was already noticing.
4-7-8 breathing (inhale for four counts, hold for seven, exhale for eight) works because the extended exhale activates the parasympathetic nervous system. The exhale is the vagal brake. A longer exhale than inhale directly tells the nervous system it’s safe to downregulate. It’s one of the fastest ways to shift autonomic state. I use it when I notice the jaw, or after a particularly sharp collision of demands.
Nature walks, when I can get out. The shinrin-yoku research on time in natural environments specifically shows measurable changes in cortisol, blood pressure, and immune markers that go beyond exercise alone. The particular sensory environment of natural settings does something distinct. I’m lucky to have countryside close. Even a park counts.
The honest ending
I want to close with the thing I said at the start of this episode and mean fully: this is not a story with a tidy resolution. My noise sensitivity is still something I work with. The mental load hasn’t gone anywhere. The children’s bickering is still hard for me to deal with.
What changed is understanding. I know what’s happening in my body now — the HPA axis, the cortisol pattern, the vagal tone, the way the circadian disruption and the stress response interweave. I no longer interpret the jaw clenching as failure. I interpret it as information. And I know what to do with it.
That shift, from “what’s wrong with me” to “what does my nervous system need right now”, is quieter than a transformation story. But it’s real. And it’s available to you even when the circumstances don’t change.
Thank you for being here ❤️
Frances
