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

As you dive down, the water pressure increases and the Partial Pressure of oxygen in your lungs and blood also increase, keeping it at sustainable level. Even as you metabolise O2 to CO2, the remaining O2 is still at sustainable partial pressure. As you swim up, the pressure drops and there’s risk of shallow water blackout.

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