Mailing List Archive

Mailing List: techdiver

Message Display

This thought occurred to me at the weekend, so I thought I should air it (no
pun intended :->) to get a more informed opinion. Please forgive any gross
simplifications or theoretical cock ups - I'm here to learn.

Basically, the uptake and release of gas by the blood in the lungs is
governed by Henry's law - and the rate of absorbtion/release depends on the
difference between the partial pressures of gas in the lungs and in the
blood. So, when I'm swimming around during my dive, I'm breathing at a
modest rate and tidal volume and the gas in my lungs is a pretty close match
to the theoretical predictions so the gas absorbed by my body should follow
 the decompresion models.  However, when I'm hanging around on a line doing
a deco stop, I become much more relaxed and expend much less effort, so my
breathing rate (and tidal volume) plummet, so the gas in my lungs is
exchanged much less frequently.

 Is it possible that the gas loadings in my lungs could get to the state
where my decompression is being slowed because the rate of release is
dropping (ie. the ppN2 in my lungs is close to the ppN2 in my blood)? Should
I make a conscious effort to breathe deeper and more often during my stops
to offset this, and would it make my stops any safer if I did?

I know that my Aladin has a 1/2 time of about 5 minutes or so as its
minimum, so I get 30 minutes without breathing to reach saturation on
that...so my gut reaction is that this shouldn't be a problem, but taking it
to its theoretical limit, a diver who didn't breathe during a stop wouldn't
off gas at all (would they?), so it follows that a slow breathing diver
should take longer than a quick breathing one.

keith
hadlandk@lg*.lo*.co*

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]