Everest at the Bottom of the Sea

Everest at the Bottom of the Sea: On diving down to the Andrea Doria. Even READING about the thrills and the risks made me a little light-headed.

[Carbon dioxide.] The natural by-product of respiration also triggers the body’s automatic desire to replenish oxygen. When you hyperventilate—take rapid, shallow breaths—you deprive yourself of CO2 and fool the body into believing it doesn’t need new oxygen. Breath-hold divers will hyperventilate before going down as a way to gain an extra minute or two of painless O2 deprivation. But at depth (for reasons poorly understood), hypercapnia, the retention of CO2 molecules, has the same “fool the brain” effect. It’s a tasteless, odorless, warningless fast track to unconsciousness. One moment you are huffing and puffing against the current, and the next you are swimming in the stream of eternity.