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Why Can Blackout Occur Without Warning?

The Question

Why can a freediver lose consciousness without strong discomfort or warning signs?


Short Answer

Because oxygen levels can fall to critical levels while carbon dioxide remains too low to trigger intense breathing distress — especially during ascent.


Deeper Explanation

(Your own explanation in plain language.)

Focus on: - physiology - pressure effects - ascent dynamics - why intuition fails

Avoid equations unless necessary.


What This Means for Freedivers

  • Why “feeling fine” is unreliable
  • Why supervision matters
  • Why ascent is critical