If the brain can only survive 4-6 minutes without oxygen, how can freedivers hold their breath for 8+ minutes?

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And what about people like David Blaine or Tom Sietas? Sietas held his breath underwater for over 22 minutes (world record). I know they train for it like months and even years, but doesn’t holding your breath = no oxygen to brain?

Permanent brain damage apparently occurs just after 4 minutes of lack of oxygen to the brain, so why are freedivers left generally unscathed after 8 or 10 minutes without air?

In: Biology

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Anonymous 0 Comments

I want to add to the other comments that when talking about 4-6 minutes without oxygen, it is also without blood supply (e.g. in case of cardiac arrest / ventricular fibrillation). While the divers still have a working circulation, oxygen is still supplied to the brain. Though indeed over time the saturation gets less, it’s not like the moment you hold your breath your saturation becomes 0. So there is technically still oxygen supply there.

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