Originally Posted by president
They flew for almost 3 hours at FL340. Had they been O2 deprived at sea level they would have been dead in minutes.
I'm not a doctor, nor a pilot, but did take a course in cardiovascular pathophysiology in the Harvard/MIT Health Science and Technology curriculum during my mis-spent years in graduate school at the 'Tute.
So FL340 offers pretty near a fifth of sea level partial pressure of oxygen--which is not much, but a very great deal more than zero. Zero is what you get when drowning or having someone shut off your air intake.
Also relevant is that individual heart muscle cells "want" to beat, and will in fact contract regularly, if still alive in a Petri dish, with no connection either to other cells, let alone a working nervous system. Furthermore, a collection of them will, usually, beat in synchrony, as the fastest will set the time, and the slower ones get reset each time the "wave" hits them.
Lastly, brain tissue "wants" much more nearly fully oxygenation to keep going than does heart, which is able to surge to much higher than resting oxygen consumption to accommodate fight or flight excursions, which are far higher above baseline as a percentage than is the range of brain activity. A resting heart does not need anywhere near full blood oxygenation. To put it another way--as you lower the blood oxygen--the CNS (Central nervous system, including but not limited to the brain) fails long before the heart.
So, I am agreeing with the report you quote--the beating hearts by no mean imply either active, nor yet recoverable, brain function.
Follow the partial pressure of oxygen, and forget this fixation on total pressure--aka altitude.
If a doctor happens along who knows better--please critique.