The most striking claim in this piece isn't about breaking records — it's that hyperventilating before going underwater is "a really bad idea." Derek Muller writes that hyperventilating expels CO2, making blood more alkaline, but it doesn't actually increase oxygen. The result: you can black out underwater before even getting the urge to breathe. This counterintuitive warning alone makes this piece worth the time for anyone curious about how their body works under pressure.
The Chemistry of Breathing
Muller walks through the physiology with precision that feels almost clinical. "The brain knows how often we need to breathe using chemical sensors called chemoreceptors," he explains, noting that these sensors detect CO2 in the carotid arteries and brain stem. When CO2 increases, blood becomes more acidic — and this acid feedback is what actually regulates breathing, not low oxygen directly. The only known chemoreceptors for low blood oxygen are also in the carotid arteries, but they play a smaller role.
This matters because it explains why the urge to breathe feels so urgent even when you have plenty of oxygen left. "CO2 is created at the same rate oxygen is used up," Muller writes, so buildup signals urgency long before oxygen depletion kicks in. The core argument here is that breath-holding is fundamentally a CO2 management problem, not an oxygen problem — and that's what makes it so counterintuitive.
Testing Your Limits
The Bolt Score test emerges as one of the piece's most practical tools. Muller describes it simply: you hold your breath and see how long until you feel that first urge to breathe. Most people last 30-40 seconds on their first try — but with practice, these numbers climb significantly. The test measures what Muller calls "body oxygen level," and it's a window into why some people naturally excel at holding their breath.
The ideal physique for breath-holding, he notes, is someone "tall and skinny with plenty of lung capacity but not too much tissue to use up oxygen." This is where lung packing becomes critical — taking a full deep breath, then continuing to sip small gulfs of air on top. Muller demonstrates this himself, packing in about 20 additional breaths after the initial inhale.
The Mammalian Dive Reflex
Perhaps the most fascinating section involves what Muller calls "our secret weapon" — the mammalian dive reflex. All humans have this physiological adaptation triggered by water contact on the face. "The trigeminal nerve in our face detects the coolness of the water and triggers a series of responses," he writes. The heart beats slower, blood vessels constrict, confining oxygen to vital organs and brain.
Muller tested this himself during his breath-hold attempt and was surprised by the results. His average heart rate dropped to 48 — "low for me that's low that's low," he admits, noting he doesn't even get that low when sleeping. The dive reflex is why free divers can stay underwater for extraordinary times: their bodies literally redirect oxygen away from extremities toward what matters most.
The Mental Game
What makes this piece particularly compelling is its focus on the psychological challenge. Muller argues that mental activity uses disproportionate amounts of oxygen — "the brain is using eighty percent of the oxygen that your body is utilizing," he says, calling it "a Biblical amount." This means calming the mind isn't just about comfort; it's a physiological strategy for reducing consumption.
The techniques he practices are surprisingly simple: going through the alphabet, practicing gratitude for each letter, singing nursery rhymes to distract the mind. But these aren't just tricks — they're measurable ways to reduce oxygen use. When Muller finally achieves 2 minutes and 36 seconds, he's genuinely surprised. "I think I can guarantee that I've never held my breath for two and a half minutes," he says.
You do not need to breathe. You have plenty more time.
This line becomes the emotional core of the piece — that urge to breathe is your body lying to you, telling you to expel CO2 when you've actually got four or five minutes before drowning. It's the most important insight: the first urge isn't the limit.
The Limits and Dangers
The record holders get their due — Branco Petrovic held his breath for 11 minutes and 54 seconds on regular air, while Brandon Burchak reached 23 minutes after breathing pure oxygen. But Muller includes a crucial warning about oxygen toxicity: "if you do that and you pass six meters or five or six meters your risk of oxygen toxicity is much higher." This isn't just academic — it's the difference between record-breaking and serious medical harm.
Brandon's underwater performance at 17 minutes shows what happens when CO2 builds to extreme levels. "You lose sense of time," Muller explains. "That's one of the ways that you know that your breath hold is over." The convulsions, the urge just plummeting — these aren't hypotheticals; they're the boundaries of human endurance.
Bottom Line
The strongest part of this argument is its reframing of what breath-holding actually demands. Most people think it's about oxygen — but really it's about managing CO2 and keeping the mind calm enough to reduce consumption. The biggest vulnerability is that most readers won't have access to a trained instructor like Brandon Burchak, so the mental strategies might seem abstract without guided practice. But for anyone curious about what their body can do under controlled stress, this piece offers both the science and the roadmap.