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> >You're on a deep dive in cold water. You're wearing your drysuit with > >normal drysuit underwear. When you have incurred a significant > >decompression obligation, you accidently rip your suit on a jagged piece > >of metal, and it floods. You immediately abort the dive, but still must > >do your decompression. On the deco line you start to become very cold, > >and due to the cold, your off-gassing efficiency is significantly reduced. > > Okay, maybe this question is a bit simplistic for this forum, but it's been bugging me for ages and now I'm going to get it off my chest ! Exactly why does diving in cold water decrease offgassing efficiency ??? I am familiar with the gas laws, and know that a cold liquid can hold a greater amount of dissolved gases. BUT the *water* is cold, not the diver's blood/plasma..... At most the diver's core temperature could drop a degree or two before he has major hypothermia problems. I had a lengthy discussion with my diving supervisor about it, and he feels that even this slight drop in core temp could affect the diffusion properties across the lung. What do you think ? If anything, the cold water would cause reduced blood flow to the extremities and result in the blood pooling around the organs (incl. the lungs). Surely this would assist offgassing ? The only reasonable thing I could come up with, is that since blood flow is reduced to the extremities and blood vessels in these areas become constricted, the diffusion of gases at the *cellular* level is inhibited. Thus the "bottle-neck" to off-gassing is in the extremities and not at the lungs. So is is not the cold directly that is the issue, but constriction of the blood vessels at the extrmeties. This is the only explanation that makes sense to me.... Am I on the right track ? (On a totally different note, does anyone know the value of 100 ECUs to US dollars or South African Rand ?) Cheers Bridget Elliott /\ /\ Department of Zoology / /\\ @@ //\ \ University of Port Elizabeth ///\ \\ (())) //\\ \ Box 1600 ////\\ ((***))//\\ \ Port Elizabeth // \ ((())/ \\ South Africa / \ 6000 fax : +27-41 - 504 2317 voice : +27-41 - 504 2424 e-mail:ZLBBLE@ZO*.UP*.AC*.ZA*
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