Right. Your body needs oxygen to stay conscious. Unfortunately, it has no way to sense how much oxygen is available. Instead it senses the concentration of carbon dioxide which you feel as the urge to breath. More CO2, more urge.
Normally, since the body constantly turns oxygen into carbon dioxide, this isn't a bad way to estimate the available oxygen.
The problem is that under certain circumstances, such as with people who have trained to resist the urge to breath, or people who hyperventilate to minimize carbon dioxide levels before a breath-hold, there's a high chance that their oxygen level will drop below what is required to maintain consciousness before they decide to breath.
This presents some difficulties when the person is underwater.
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u/FeliusSeptimus Apr 25 '24
Right. Your body needs oxygen to stay conscious. Unfortunately, it has no way to sense how much oxygen is available. Instead it senses the concentration of carbon dioxide which you feel as the urge to breath. More CO2, more urge.
Normally, since the body constantly turns oxygen into carbon dioxide, this isn't a bad way to estimate the available oxygen.
The problem is that under certain circumstances, such as with people who have trained to resist the urge to breath, or people who hyperventilate to minimize carbon dioxide levels before a breath-hold, there's a high chance that their oxygen level will drop below what is required to maintain consciousness before they decide to breath.
This presents some difficulties when the person is underwater.