3 ms·

Yes, it’s crucial in fact.

• petodo 4y ago
  I remember reading about it, but care to explain simply why it helps?
  • TamDenholm 4y ago
    Not an expert but my basic understanding is that the hyperventilating before holding your breath basically oxygenates your blood so that you can hold for longer.
    • postsantum 4y ago
      No, that's because hyperventilation washes out CO2 so the CO2 alarm going off later than usual