March 15, 2013

A question answered

About two years ago, two young guys drowned in a public pool on Staten Island. At least one was planning to take the test to join the Navy Seals. It is assumed that they were practicing holding their breath. In any case, they drowned in fairly shallow water during the exercise.

I couldn't understand it. How could two young, healthy guys drown? You run out of air, you pop up and breathe, no? But today, while I was reading a story about drowning, I encountered this explanation of what drowning is like:
Osinski says one of the most subtle forms of drowning is called "shallow water blackout."

Typically, a person holding his breath will be triggered to breathe when his CO2 levels get high. But if a swimmer is holding his breath for a long time while exhaling underwater, or is going underwater repeatedly, his CO2 levels are lowered. When that happens, the brain's built-in alarm to breathe doesn't go off, despite a lack of oxygen.

"You can't tell when they go unconscious, until it's too late," Osinski says.
Their brain alarms didn't go off, they passed out and they drowned. Mystery solved. It's still a very sad thing, but at least I understand it now.

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