> ---------- > From: Major Variola (ret)[SMTP:[EMAIL PROTECTED]] > Sent: Friday, November 01, 2002 6:02 PM > To: [EMAIL PROTECTED] > Subject: Re: Flight security analysis (was Re: Confiscation of > Anti-War Video) > > At 05:16 PM 11/1/02 -0500, Steve Furlong wrote: > >But Maj Variola made a questionable point, too: > > > >> At 30K feet, you have about half a minute before you pass out > > > >I just tested that, sort of. I emptied my lungs, then lifted weights > for > >30 seconds. It was a little painful toward the end, but I didn't grey > >out or anything. > > I was unable to find my ref. But I also know that muscles > can work anaerobically; also that asphyxiation-feeling is from > too much CO2, not a lack of O2. Also, you can't really > empty your lungs. > > I once saw a show about medicine. In it, an M.D. rebreathed > his own CO2-scrubbed air as he wrote the alphabet, on camera. > Halfway through he started scribbling incoherently and fell over, > unawares. > (There were assistants to save him.) > > FWIW > I did this something similar once myself, in high school biology (this was in Britain, so there were no bullshit concerns over liability). Two students, one rebreathing scrubbed air, the other (me) unscrubbed (ie, I was rebreathing my own CO2).
I kept going about 2 minutes before I started to black out. Analysis of the air showed that it still had substantial oxygen content, but the CO2 level had tripled. My partner, who rebreathed CO2 scrubbed air, kept going for 7 or 8 minutes before stopping, and had used a much higher fraction of the O2. It turns out that CO2 has substantially higher affinity for haemoglobin than does O2, so the CO2 was suffocating me even in the presence of ample oxygen. Carbon monoxide has an even higher affinity, which is why it's so poisonous. Peter Trei
