dteubner

The problem is that it would be very difficult to do away from a spreadsheet.

Lets say you are at 30m any your hypoxic mix has an FIO2 of 0.04. If you took one breath from the O2 and two from the mix and they are 4 litre breaths from your 7 litre lungs then, at steady state, your fraction of oxygen in the alveoli varies between about 64% after the O2 breath to 14% after the second mix breath and your mean (whatever the hell that means physiologically) PPO2 is 1.44 - which sort of looks like a good number. If you take smaller breaths then the steady state mean doesn't change but the fluctuations are much smaller (1.64 to 0.47 for 1 litre breaths)

I guess what no one can say what the risk of O2 toxicity is when you are at 2.5, 1.2 and 0.6 ATAs for 6 seconds each recurringly, and what the decompression implications of this are is anyones guess.

Of course you can't take exactly 4 litre breaths over and over again so what your PO2 is would be impossible to know and vary accross a very wide range (what's that rule again?)

I think at best you could use the technique to swim from where your dil is too hypoxic to where your O2 is sort of breathable but my gut feeling is you would very likely fit if you tried to do any stops on the way - and you would have no way of knowing what the stops would mean anyway.

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Dave T

Hanlon's Razor - Never attribute to malice that which can be adequately explained by stupidity.