Perched 570 meters above sea level on the rocky slopes of Mount Parnassus, the sanctuary at Delphi was the center of the ancient world. Not just metaphorically- at the time,  people actually believed it was the literal navel of the earth. Kings sent messengers here before going to war. Politicians sought counsel before founding new cities. Farmers asked which crops would produce the best harvest.

At the center of it all sat one woman.  Well, many women, over many years, who all served one role: that of the Pythia. The Oracle.

Relatively little is known about the Pythia.  Scholars believe that, because she was such an integral part of life and culture, writers never bothered to explain her or offer background when referencing her.  But there are some things that have become clearer with time.

The Pythia sat above a narrow fissure in the earth, draped in laurel, breathing deeply the vapors that rose from below, somewhere deep in the rock. The ancients called it pneuma. Divine breath. The breath of Apollo himself.

Some ancient accounts describe the Pythia as agitated but coherent, speaking in fragmented bursts that priests then interpreted. Others describe a calmer scene.  But, whatever the case, it is clear the Pythia experienced an altered neurological state — one that allowed her to prophesize and channel the God Apollo in a way that made her one of the most powerful people of the time.

For nearly a thousand years, the Oracle at Delphi was consulted as the highest authority in the Greek-speaking world. That's not a typo. A thousand years. Whatever was happening in that chamber — whatever the Pythia was experiencing — it was considered reliable enough, credible enough, and consistent enough, that civilization was organized around it.

So. What do we think was actually going on?

Delphi sits at the intersection of two major fault systems: the Kerna fault and the Delphi fault. These faults cut through bituminous limestone — the kind of rock that, when fractured and pressurized, releases gases. In 2001, geologist Jelle de Boer published research confirming what some historians had suspected: the sanctuary at Delphi was seeping ethylene, methane, and CO₂ through the rock beneath the temple floor.

Let’s explore what those gases actually do to a body that's breathing them.

Ethylene, even at low concentrations, crosses the blood-brain barrier and acts as a mild anesthetic -  slowing the ordinary, analytical chatter of the mind while leaving a person functional and aware. Methane displaces oxygen in the immediate environment, subtly reducing the amount of oxygen available with each breath - not enough to cause distress, but enough to shift the brain's oxygen balance. And CO₂, when it accumulates in the bloodstream, triggers the brain's ancient alarm system: breathe differently, breathe now. The breath becomes involuntarily deeper and more rapid.

Here's why that matters cognitively: when CO₂ rises and oxygen drops even slightly, the brain's prefrontal cortex — the seat of linear logic, self-editing, and skeptical analysis — quiets. What remains more active are older, deeper structures: the limbic system, the areas associated with pattern recognition, emotional processing, and what we might call symbolic knowing. The Pythia was, in a very real neurological sense, shifting consciousness — temporarily released from the cognitive filter that normally keeps us locked in ordinary, literal thought.

We can’t know if the Oracle was divinely possessed in the way the ancients imagined. But we can guess that what she was experiencing was very real. She was assuredly influenced by her beliefs, likely wired for high sensitivity, and, almost undoubtedly,  in a genuine, chemically-mediated altered state influenced by breath (her own and that of the earth). In this state she may well have been exceptionally attuned to intuitive perception and the energies of the Universe.

Pneuma - literally "breath" or "wind" - is one of the central concepts in Greek medicine and philosophy. For the Stoics, pneuma was the animating life force that moved through all living things. For the physician Galen, it was the medium through which the nervous system transmitted sensation and movement. They didn't have the vocabulary of neuroscience, but they were reaching for the same thing: breath as the regulatory medium of life itself.

They weren't alone. Across cultures and centuries, the same insight keeps surfacing:

Different languages, different cosmologies, even different parts of the planet. All coming to the same fundamental observation: breath is not just air exchange. It is something else. Something that touches consciousness itself.

Turns out they were right.

When Galen described pneuma flowing through the nervous system to animate the body, he was reaching - without microscopes, without chemistry, without any of our modern tools — for what we now call the autonomic nervous system. The breath-regulated, vagus-nerve-connected system that governs everything from heart rate to digestion to emotional regulation.

Here's the neuroscience our ancestors perceived experientially:

CO₂ and altered states: The research on breathwork-induced altered states — holotropic breathing, Wim Hof method, pranayama — consistently shows that deliberate manipulation of CO₂ levels in the blood produces measurable shifts in consciousness. Reduce CO₂ rapidly (as in hyperventilation) and you get tingling, altered perception, sometimes visionary states. The experience may well be mystical. But it's also blood gas dynamics directly affecting brain activity.

The default mode network: When ordinary, goal-directed thinking quiets down — when the brain's "default mode network" (the part associated with self-referential thought, rumination, and planning) goes offline — something interesting happens. People report feelings of connectedness, insight, expanded perception, and what researchers studying psychedelics and meditation are now calling "mystical experiences." Breathwork is one of the clearest ways to produce this state without substances.

The Pythia, sitting above volcanic gas, most likely in a state of chemically-altered consciousness, was also likely doing involuntary holotropic breathing. The modern practitioner lying on a yoga mat doing intentional breathwork is chasing the same neurological state through slightly different means.

The mechanism — whether divine breath or CO₂ dynamics — matters less than the fact that humans have known for millennia that breath is a door to a different consciousness.

Here's the theme I always get so excited about: across every culture, on every continent, the same important discoveries get made. Even if the tools, lenses, and language are different -n we are talking about the same things.

In this case it is that breath is not just oxygen in, carbon dioxide out. It is the most accessible lever we have for shifting our nervous system, altering our state of consciousness, and moving between stress and ease, between contraction and expansion, between ordinary mind and something a little wider.

The Greeks tapped into geological phenomena to help them access this. A fault in the earth's crust leaked just enough ethylene that they chose the site for their most sacred ritual, placing a woman directly above it, so that in her altered state she could share the insights she gained- although they did need to be translated by priests first!.

Those of us that aren’t the Pythia, don’t have an Oracle, and aren’t in Delphi can still access this state. It just takes learning the right breath patterns. No fissure required.

⚠️ Not recommended if you have cardiovascular conditions, are pregnant, or have a history of seizures. If you feel dizzy or uncomfortable, return to normal breathing immediately. As always… LISTEN TO YOUR BODY!

This is a simple holotropic-adjacent practice. You don't need a volcano. You just need about five minutes and a quiet place to sit.

Sit comfortably with your spine long. Take 30 connected breaths — in through your nose, out through your mouth, no pause at the top or bottom, at a moderate pace. Let each exhale release completely before the next inhale begins. 

Don't force it. Don't rush.

After your 30th breath, sit quietly. Do nothing. Notice whatever arises — tingling, warmth, a shift in how the room feels, a loosening of ordinary thought. Stay there for a few minutes before returning to your day.

What's happening: You're gently shifting your CO₂ levels, which alters the brain's chemistry in subtle, measurable ways. For many people, even this brief practice produces a noticeable shift in perception — a softening, a widening, a moment of something that feels almost like coming up for air.

The Oracle at Delphi was famously consulted for her wisdom- wisdom she likely gained while engaged in powerful breath practice influenced by breathing volcanic gas — specifically ethylene — that seeped through fault lines beneath the temple floor. Ancient Greek philosophers built an entire theory of consciousness (pneuma) around what she experienced. Modern science confirms that breath profoundly alters consciousness through CO₂ dynamics, default mode network suppression, and autonomic nervous system shifts — which explains why every culture on earth independently arrived at the same conclusion: breath is a door to something more than ordinary waking life.

Whether that something is neuroscience or the divine — we're not ruling anything out.

Ready to explore more practices at the intersection of ancient wisdom and modern science? Check out our blog.