It was early July. The kind of Scottish morning that almost convinces you the summer is going to hold — low light coming in at an angle through the garden, that particular quality of stillness you only get before the city fully wakes. I was outside with an espresso and Dexter.
Dexter was settled on the grass. Not asleep. Not alert. Somewhere between the two — that particular low-to-the-ground ease that dogs achieve without effort and without apparent instruction. Nose working slowly through whatever the morning air was carrying. Completely, entirely here.
I had my phone in my hand. I was thinking about a client I’d seen the day before, running through something I should have said differently. I was also thinking about a talk I’m preparing, whether the structure works. And somewhere underneath both of those, a persistent low-level monitoring of the week ahead.
I looked at Dexter. I looked at my phone. I put the phone down.
The espresso was excellent. The garden was green in the way Scottish gardens are green in July, which is a different green from any other country’s July. The light was doing the thing it does here at this latitude — soft, directional, unhurried. Dexter’s ear twitched at something I couldn’t hear.
Five minutes, maybe. Genuinely nowhere else.
It struck me that I spend a considerable amount of professional energy on this question — about stress, about the nervous system, about the physiological cost of a mind that won’t stay where the body is — and that I am not especially good at the practice of it myself. That the dog was doing it better than me. And that this was worth writing about.
Where the mind goes when you’re not watching it
The brain has a default. When it is not engaged in a specific task — when you are not actively reading, solving, or attending — it doesn’t go quiet. It activates a network of regions that neuroscientists have called, with characteristic directness, the default mode network.
The default mode network is primarily concerned with three things: remembering the past, imagining the future, and thinking about other people. It is the network of self-referential processing — the mind talking to itself about itself, its history, its concerns, its relationships, its plans.
This is not pathology. It is architecture. The capacity to mentally simulate future events, to learn from past experience, to model other minds — these are profound cognitive achievements. The default mode network is part of what makes humans human.
The problem is not what the network does. It is how much time it runs, and on what content.
Killingsworth and Gilbert (2010) in Science tracked nearly 2,250 adults via smartphone at random intervals throughout the day, asking what they were doing, what they were thinking about, and how happy they were. The results were striking: people were mind-wandering — thinking about something other than what they were currently doing — 46.9% of the time. Mind-wandering predicted unhappiness significantly more reliably than activity type did. The authors concluded: “A human mind is a wandering mind, and a wandering mind is an unhappy mind.”
Crucially, the content of the mind-wandering mattered. Neutral or pleasant mind-wandering was less harmful than negative rumination — but both were associated with reduced present-moment wellbeing compared to task-focused attention, regardless of the task.
Almost half your waking hours spent somewhere other than where you are. That is not a small number. And the question I want to pursue here is not simply whether this makes you feel less happy in a general sense — it is what it does to the body, specifically, when the somewhere-else your mind is visiting is a place of worry, rehearsal, or regret.
Mental time travel and the stress response
The hypothalamic-pituitary-adrenal axis — the HPA axis, the body’s primary stress response system — does not distinguish between a threat in the room and a threat in the mind. This is the central physiological fact that makes rumination so costly.
When you sit quietly and replay a difficult conversation, anticipate a future confrontation, or rehearse a scenario you are worried about, the HPA axis responds. Cortisol rises. Sympathetic tone increases. The body prepares for a threat that exists only in the prefrontal cortex.
This is not a design flaw. In short bursts, the ability to mentally simulate threats allows preparation and avoidance — it is adaptive. The problem is duration and repetition. A stress response that activates and resolves is physiologically manageable. A stress response that runs in a low-grade loop through most of the waking day, driven by a mind that keeps returning to the same anxious content, creates exactly the kind of chronic cortisol pattern that disrupts sleep, suppresses immune function, impairs gut motility, degrades hormone production, and accelerates biological ageing.
The body is always in the present. It is only the mind that travels. But wherever the mind goes, the body follows — neurologically, hormonally, immunologically.
I see this in test results regularly. Elevated evening cortisol in clients who describe themselves as “overthinkers.” Flattened cortisol curves in people who have been running on low-grade vigilance for years — the HPA axis eventually adapting downward from the chronic demand. Disrupted sleep architecture that traces back not to a sleep problem but to a mind that won’t disengage from its default mode processing at bedtime.
The DUTCH Plus — which gives us a full cortisol curve across the day and into the evening — is one of the most revealing tests I run for this pattern. Elevated cortisol at 10pm in someone who sits quietly reading before bed is not a reading problem. It is a rumination problem. The body is responding to whatever the mind is doing, and the mind is not reading.
The past and the future are both abstractions
There is a distinction worth making between useful engagement with the past and future versus chronic unconscious revisiting of them.
Reflecting deliberately on a past experience in order to understand it differently — that is integration. Making a specific plan for a future event in order to reduce uncertainty — that is preparation. Both are purposeful, time-limited, and serve the present.
What chronic mental time travel looks like is different. It is the same replay running again without resolution. The same future worry activated again without new information or decision. The same rumination loop that doesn’t produce insight because it never quite finishes — it just pauses long enough for something external to interrupt it, then restarts when the interruption ends.
The nervous system reads these not as thinking but as threat detection. Each activation is another cortisol signal. Each return to the same anxious content is another sympathetic nudge. Over months and years, the cumulative physiological cost is substantial.
The past is a memory. The future is a projection. The present moment is the only thing that is actually occurring. This sounds like a cliché — and it is one — but it is also a physiological fact with measurable clinical consequences.
What presence actually does to the body
Mindfulness research has been through a period of significant hype and subsequent more careful scrutiny. Some early claims were overstated. The effect sizes for some outcomes are more modest than the popular literature suggested. I try to hold this honestly.
What the more rigorous end of the research does support, consistently:
- Reduced cortisol response to psychosocial stress in regular meditators compared to controls
- Reduced default mode network activity and reduced rumination with sustained mindfulness practice
- Improved sleep quality, particularly reduced sleep-onset latency and improved slow-wave sleep
- Reduced inflammatory markers — particularly IL-6 and CRP — in chronic stress populations
- Improved heart rate variability, a marker of vagal tone and autonomic flexibility
These are not trivial outcomes. They map directly onto the physiological mechanisms that chronic rumination disrupts. The body under genuine present-moment awareness is running a different set of processes than the body under chronic mental time travel. The HPA axis is quieter. The immune system is less driven by cortisol suppression. The gut — innervated by the vagus nerve, highly sensitive to autonomic state — functions differently.
In clients with elevated evening cortisol on the DUTCH Plus who describe persistent overthinking, sleep difficulty, and gut symptoms, I often find that the gut findings are secondary to the nervous system findings. The dysbiosis, the motility issues, the digestive enzyme insufficiency — these don’t resolve fully until the autonomic pattern shifts. Functional nutrition is necessary but not sufficient. The missing variable is often nervous system regulation.
This is not a reason to avoid the testing. It’s a reason to take the lifestyle component — including present-moment practice — as seriously as the clinical intervention.
The argument against presence — and why it’s partly right
There is a version of the present-moment argument that I find incomplete, and I want to name it.
The idea that the present moment is always preferable to past or future — that any engagement with what was or what might be is somehow a failure of awareness — misses something important. Some of the most valuable things human beings do happen in the not-now. Grief requires dwelling in what has been lost. Planning requires imagining what hasn’t happened yet. Creativity often works through a kind of productive elsewhere. A person who could not access past or future would not be enlightened — they would be cognitively impaired.
The question is not whether to use past and future, but whether the default mode network is running the past and future at you without your choosing it. The difference between deliberately sitting with a memory to understand it and having the same painful memory activate involuntarily at 2am is the difference between use and symptom.
The clinical target is not a mind that never leaves the present. It is a mind that can return to the present — that has enough regulatory capacity to interrupt the automatic loop and choose where to direct attention. That capacity is trainable. And the training is simple, if not easy.
What the practice actually looks like
I am cautious about prescribing specific mindfulness protocols, partly because the research on which formats produce which outcomes is still developing, and partly because individual variation in what works is significant. What I can say is what I have found useful, and what I have observed in clients.
The single most accessible entry point is sensory grounding — deliberately bringing attention to what the senses are receiving right now. Not what they were receiving earlier, not what they will receive later. The temperature of the air. The weight of the body in the chair. The specific sounds present in this moment, not as background noise but as distinct objects of attention.
This does not require a meditation cushion or a specific practice. It requires a pause, and a deliberate redirect. Two minutes done consistently is worth more than twenty minutes done intermittently and resentfully.
Breathing is the most portable anchor. The breath is always in the present — you cannot breathe yesterday’s breath or tomorrow’s. Slow, deliberate, nasal breathing activates the parasympathetic system via the vagus nerve. The physiology and the psychology are working in the same direction: slow the breath, slow the mind, return to now.
Time outdoors matters more than the mindfulness literature sometimes acknowledges. There is something specific about natural environments — light quality, acoustic complexity, the non-linearity of organic shapes — that appears to reduce default mode activity and facilitate genuine present-moment attention in ways that indoor environments do not replicate. This is not mysticism. It has measurable neurological correlates, and spending time in the research is time well spent.
Back to the garden
Dexter eventually got up, did a slow circuit of the garden perimeter — nose to the ground, entirely absorbed in whatever narrative the grass was telling him — and came back to settle at my feet.
He had not, as far as I could tell, spent any of the previous fifteen minutes thinking about yesterday’s walk or tomorrow’s dinner. He had been in the garden. Fully, completely, without apparent effort.
I am not suggesting we aspire to the inner life of a Labrador. There is something to be said for the capacity to worry about the future — it has driven most of what I’ve built over the past thirty-seven years. But there is also something to be said for the discipline of putting the phone down, finishing the espresso, and being where you are while you are there.
The body will thank you for it. The tests, if you run them, will show you why.
If your cortisol pattern tells a story, we should read it together
The DUTCH Plus gives a full diurnal cortisol curve — morning, noon, afternoon, evening, and night. If the pattern is elevated when it should be falling, or flat when it should be rising, there is clinical information there worth acting on. Book a free discovery call to find out if testing makes sense for you.
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