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From: andrewt@cs.su.oz (Andrew Taylor)
Newsgroups: sci.bio
Subject: Re: High Preasure
Message-ID: <567@cluster.cs.su.oz>
Date: 6 Oct 89 00:08:37 GMT
References: <16770@watdragon.waterloo.edu>
Sender: news@cluster.cs.su.oz
Reply-To: andrewt@cluster.cs.su.oz (Andrew Taylor)
Organization: Basser Dept of Computer Science, University of Sydney, Australia
Lines: 16

>But this got me thinking, what limits the depth that humans can dive to (I
>mean, besides comming up)?

I've seen speculation that the maximum pressure that the human body can
withstand (the rib cage crushes?) is ~ 80 atmospheres (= a depth of 800 metres).
Some other limits are (roughly)

10 metres  - breathing pure oxygen is lethal
50 metres  - nitrogen narcosis is a serious problem (breathing air)
100 metres - breathing air is lethal (nitrogen narcosis/oxygen toxicity)
           - breathhold diving record
300 metres - breathing helium causes nervous system problems
	   - ~ scuba diving record
500 metres - simulated diving record (in a pressure chamber)

Andrew