The Quietening Self: What freediving, meditation and neuroscience can teach us about getting out of our own heads

A personal, research-informed essay | Tania Douthwaite | Blueback Freediving & Yoga

Approximately 10 - 15 minute read

Figure 1: The author enjoying a moment of self-quieting off Gull Rock, Ngari Capes Marine Park, Western Australia. Photo credit: Tao Huang.

A moment beneath the surface

Several years ago, I was guiding a group of freedivers on a charter off Wadjemup - Rottnest Island, Western Australia. Our boat had anchored near the remains of an old shipwreck. After delivering my usual safety briefing, the divers entered the water in their buddy pairs. Our lookout monitored the group from the boat while I supervised their safety from the water.

Once I was satisfied that everyone was buddying responsibly and the group’s safety arrangements were working well, I had an opportunity to enjoy a freedive myself. I settled into my familiar relaxation routine at the surface, took a final full breath and descended towards the wreck.

Shoals of fish gathered around the remains of the vessel, a living piece of maritime archaeology. As I swam down through them, I reached neutral buoyancy and began to sink effortlessly towards the seabed. Reaching the bottom, I settled gently onto the soft sand and lightly held a piece of wreck protruding from the seafloor. And I relaxed.

My whole body felt profoundly peaceful. Nothing around me seemed alarmed or even particularly interested in my presence. The fish continued moving through the water. Seaweed swayed in the current. I rested quietly within this living environment.

Then the familiar boundary between myself and the world around me seemed to fade. I wasn’t simply observing the underwater environment. For those moments, I felt as though I had become part of it. I felt the movement of fish and seaweed within an expanded field of awareness.

The closest analogy I can offer is the way we can direct attention to the tip of a finger and then expand our awareness to the sensations of the whole body. Underwater it felt as though my sense of self had expanded beyond my body to encompass the surrounding environment. I hadn’t lost consciousness. I felt extraordinarily present. But the familiar sense of being a separate ‘I’ had softened.

Eventually it was time to return. I ascended, completed my recovery breathing and resumed my familiar role guiding the group. Yet that experience stayed with me. It wasn’t a dive to fifty metres or a test of my limits. It was an ordinary part of my working life as a freediving instructor and wilderness guide, and it was profoundly beautiful.

Looking back, what stayed with me was not simply the scenery but how I experienced myself within it. I was not separate from the living world, looking in. For a moment, I felt I belonged within it.

What happens when the self becomes quiet?

As a marine scientist, freediving instructor and founder of Blueback Freediving & Yoga, I’ve become increasingly curious about experiences like this. What changed in that moment? Was I simply deeply relaxed, so absorbed by my surroundings that my internal commentary fell away? Or had something changed in the way my mind constructed the boundary between myself and the world?

Freediving can offer something quite different from the physical achievements traditionally associated with the sport. Some of the most meaningful moments have little to do with depth or duration. They concern how we experience ourselves and our relationships with the ocean.

Neuroscience offers a way to ask more precise questions without pretending it has already explained my dive. Perhaps becoming less preoccupied with our habitual story of ourselves leaves room for a more expansive experience of belonging.

Figure 2: A freediver appears through a shoal of pomfred, off Goomburrup - Bunbury, Western Australia. Photo credit: Blueback Freediving & Yoga.

The brain that never stops talking about us

Much of waking life involves remembering conversations, imagining the future, evaluating ourselves and wondering how others perceive us. These abilities help us plan and maintain relationships. They can also become exhausting when worry and rumination take over.

Neuroscientists describe a set of interacting brain regions called the default mode network, or DMN, involved in autobiographical memory, future thinking, mind-wandering and aspects of self-referential processing. In a study of experienced meditators, Brewer and others (2011) observed reduced activity in key DMN regions during several meditation practices, alongside differences in connectivity.

The DMN is not an ‘ego centre’, nor is reducing its activity the same thing as eliminating the self. Its functions are valuable and complex. Still, the research suggests that contemplative practice can change our relationship to the ongoing narrative of ourselves. I cannot know what my DMN was doing off Wadjemup - Rottnest. The science offers a lens for curiosity, not a retrospective diagnosis.

Quietening thought is not the same as quietening the self

A sleepy person and an intensely attentive meditator may both report having fewer thoughts. Yet fewer thoughts, less self-referential thought and less consciousness are different experiences. A useful philosophical distinction is between the narrative self—the story we tell about who we are—and the experiential self, our immediate sense of being present. These are conceptual distinctions, not isolated brain modules. We might become less absorbed in autobiographical thinking while remaining vividly aware of sounds, sensations and surroundings.

My memory of the wreck is of presence rather than absence. The interesting question is whether a quieter personal narrative can sometimes accompany an expanded sense of connection, without our assuming all such experiences share one neurological mechanism.

Yoga Nidra, Pratyahara and the starting state of mind

In classical yoga, Pratyahara concerns the regulation or withdrawal of attention from habitual sensory distractions. Contemporary Yoga Nidra practices often use guided body awareness, breath observation, imagery and relaxation. Depending on fatigue, experience and instruction, the same session might lead one person towards sleep and another towards subtle bodily awareness.

In a 2024 functional MRI study, Fialoke and others investigated Yoga Nidra in experienced meditators and novices. Experienced practitioners showed decreased connectivity in parts of the default mode network during Yoga Nidra relative to rest, while novices showed increased connectivity. These findings suggest that practice history matters; they do not tell us exactly what every participant consciously experienced.

This is especially interesting to me because it cautions against treating ‘meditation’ as one fixed brain state. The practice, the person and the state they bring to it all matter.

Figure 3: Freedivers practise yoga asana, pranayama, and meditation as ways to improve self-quieting in Exmouth Gulf, Nyinggulu-Ningaloo, Western Australia. Photo credit: Blueback Freediving & Yoga.

Interoception: becoming aware of being alive

Interoception is the nervous system’s sensing and integration of information from within the body: breathing, heartbeat, internal organs, temperature and many other signals. It includes processes outside awareness as well as sensations we consciously notice (Khalsa et al., 2018).

During contemplative practice, subtle sensations may become more noticeable without greater self-consciousness. We might feel the diaphragm move, the heartbeat change, or a muscle release. Importantly, noticing more sensations does not automatically mean perceiving them more accurately. That distinction helps explain why self-quietening need not mean becoming numb. In some moments, awareness of being alive seems unusually vivid even as the commentary about ourselves grows

quieter.

Freediving, presence and physiological safety

Freediving changes how we move, hear, sense pressure and inhabit space. Focused attention, learned relaxation, water immersion, sensory changes, the underwater environment and our emotional response to nature might all contribute to the experience of presence. We should not assume that this state is neurologically identical to meditation.

Breath-holding also changes physiology. Oxygen is consumed while carbon dioxide generally rises; carbon dioxide contributes to the urge to breathe and influences cerebral blood flow. Feeling calm or comfortable is not a reliable indication of adequate oxygen. Hyperventilation can delay the urge to breathe while increasing blackout risk, and decreasing pressure on ascent can worsen the risk of hypoxia.

At Blueback, this distinction is fundamental. Altered consciousness through oxygen deprivation is never a goal. Freediving demands suitable instruction, skilled and attentive buddies, professional safety systems where applicable, and a commitment to returning safely. The meaningful experiences I am describing are invitations to attention, not reasons to push physiological limits. Never practise breath-holding alone in water.

The unanswered question of endogenous DMT

Another field of research raises intriguing—but often overstated—questions about altered states of consciousness. DMT, or N,N-dimethyltryptamine, is a tryptamine that can produce profound perceptual changes when administered externally. Researchers have also found evidence of naturally occurring, or endogenous, DMT in mammalian tissues. Its ordinary physiological role remains uncertain (Barker, 2018).

The body can produce DMT through biochemical steps involving tryptophan, tryptamine and the enzyme indolethylamine N-methyltransferase. But identifying a possible synthesis pathway does not tell us how much DMT is released in living human brains or when.

Dean and others (2019) measured extracellular DMT in rat brains (in a study we felt very uncomfortable to read about) and reported increases after experimentally induced cardiac arrest, including in animals without intact pineal glands. This was a rat

experiment involving cardiac arrest—not a study of healthy people, ordinary breath-holding or freediving. It did not demonstrate that DMT caused a subjective psychedelic experience.

In a different research context, Timmermann and his colleagues (2023) used EEG and functional MRI to study externally administered DMT in humans, revealing substantial changes in brain dynamics and connectivity. These pharmacological effects cannot be used as proof that meditation, Yoga Nidra or freediving induces a similar DMT state.

I find these investigations fascinating precisely because there is so much we do not know. DMT does not currently explain my experience at the wreck, and there is no established evidence that freediving releases psychedelic quantities of endogenous DMT.

Different pathways to a quieter self

Meditation may change our relationship to self-referential thinking. Yoga Nidra may shift relaxation, attention and awareness of the body. Freediving may combine trained attention with immersion, physiological change and fascination with a living environment. Pharmacologically induced states involve other mechanisms again.

People may describe a softened sense of self across these different settings, but similar descriptions do not establish the same neurochemistry or network activity. Perhaps one fruitful research question is not whether all these states are identical, but how attention, sensory experience and self-related processes can be reorganised in different ways.

From self-quietening to ecological connection

For Blueback, this is where the questions become deeply personal. When I recall the wreck, I remember the fish moving around me and the seaweed swaying with the current. I remember an experience not of conquering an environment but of belonging within it.

Psychologists have studied the feeling of awe that can arise when we encounter something vast or beyond our usual frame of understanding. Piff and colleagues (2015) investigated the ‘small self’: a shift in the relative importance of personal concerns in the presence of something larger. This need not mean diminished self-worth; it can mean becoming less central to our own attention.

That possibility resonates with me, although awe and meditation should not be assumed to act on the brain in precisely the same way. In the sea, knowledge and direct experience can complement one another. Knowing that a seaweed forest provides habitat is one thing; watching a small fish shelter among its fronds is another.

Environmental psychologists use the term nature connectedness for the felt sense of relationship or identification with the natural world. Research has linked nature connectedness with wellbeing and pro-environmental attitudes and behaviour, although causality and the strength of effects vary between studies. A peaceful freedive does not automatically produce environmental stewardship. But repeated

encounters, attention, knowledge and community might help cultivate care.

Figure 4: A freediver enters the peace and quiet of blue space off Penida Marine Park, Bali, Indonesia. Photo credit: Chiara Bussini.

Discovering the ecological self

When I first encountered the philosophy of deep ecology in my first undergraduate Philosophy degree at Edith Cowan University in 2002, I was struck by its resonance with some of my experiences underwater - as someone exploring freediving as a way to restore myself and deepen my connectoin to the natural world. Philosopher Arne Næss described the ecological self as an expanded identification with other living beings and ecological systems (Næss, 1987). From this perspective, care for nature might arise not only from duty but from recognising our participation in a larger living world.

I think back to the wreck. I did not literally become a fish or perceive through the seaweed. What changed was the felt boundary of my own awareness. It seemed to expand from the body into the surroundings, rather like moving attention from the tip of a finger to the sensations of the whole body—only this time, the larger field felt like the ocean itself.

This is a first-person description, not a neuroscientific demonstration of Næss’s philosophy. But the parallel is meaningful to me. It invites a question that sits at the heart of Blueback: might learning to enter the ocean with skill, humility and attention also help us discover ourselves as participants within its living systems?

That is one reason we combine freediving education, yoga, mindfulness, marine science and community. We want people not only to feel more capable underwater but also to develop relationships with the places and living beings they encounter. Curiosity can become familiarity; familiarity can invite attention; attention can support care.

What remains unanswered?

Does contemplative experience change how readily our personal narrative quietens? How do alertness and practice history influence Yoga Nidra?

What happens in the brain during safely conducted freediving?

Does endogenous DMT have biological functions unrelated to psychedelic experience? Can transient moments of self-quietening contribute to enduring wellbeing or ecological connection?

These questions deserve careful investigation. Personal experience, neuroimaging, physiology, philosophy and environmental psychology offer different kinds of evidence; none should be substituted uncritically for another.

Finding ourselves in the quiet

I return often to that ordinary day at Rottnest. It reminds me that meaningful freediving is not necessarily about depth, duration or extraordinary performance. Sometimes it is the quiet, receptive way we inhabit the water.

We can be vividly aware without constantly thinking about ourselves. We can feel the body without continually narrating it. We can encounter the natural world not simply as a place we visit but as a living system to which we belong.

Perhaps quietening the self does not mean losing who we are. Perhaps it allows us to experience more fully what we are part of.

Discover your Ecological Self.

References and further reading

Barker, S. A. (2018). N,N-Dimethyltryptamine (DMT), an endogenous hallucinogen: past, present, and future research to determine its role and function. Frontiers in Neuroscience. https://doi.org/10.3389/fnins.2018.00536

Brewer, J. A., et al. (2011). Meditation experience is associated with differences in default mode network activity and connectivity. PNAS. https://doi.org/10.1073/pnas.1112029108

Dean, J. G., et al. (2019). Biosynthesis and extracellular concentrations of N,N-dimethyltryptamine (DMT) in mammalian brain. Scientific Reports. https://doi.org/10.1038/s41598-019-45812-w

Fialoke, S., et al. (2024). Functional connectivity changes in meditators and novices during yoga nidra practice. Scientific Reports. https://doi.org/10.1038/s41598-024-63765-7

Khalsa, S. S., et al. (2018). Interoception and mental health: a roadmap. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. https://doi.org/10.1016/j.bpsc.2017.12.004

Næss, A. (1987). Self-realization: an ecological approach to being in the world. The Trumpeter. https://www.trumpeter.athabascau.ca/index.php/trumpet/article/view/623

Piff, P. K., et al. (2015). Awe, the small self, and prosocial behavior. Journal of Personality and Social Psychology. https://doi.org/10.1037/pspi0000018

Timmermann, C., et al. (2023). Human brain effects of DMT assessed by EEG and fMRI. PNAS. https://doi.org/10.1073/pnas.2218949120