Posted by John Walker on January 05, 2001 at 17:50:57:
In Reply to: Re: Feeling good posted by Jim Hoffmann on January 05, 2001 at 10:07:09:
Jim, your right. Nitrogen is the bad guy. Just about any general anestesiological literature will support the theory that ALL gases will on-gass and off-gas in tissues at the same rate except in FAT. This could make for a more linear profile if we had either no fat or no nitrogen. An easy reference for divers would be from Jolie Bookspan PHD.
Fat is an important part of our physiology and NITROGEN is highly soluable in it. Once nitrogen enters the fat it becomes retained much longer than any other breathing gas used in diving.
A lot of the diving fatigue is (I believe) brought on by the inflamatory effects of this nitrogen gas perfusing through tissue at such a high gradient. Meaning that the nitrogen tissue pressure is MUCH greater than ambient pressure allowing gas to grow, maybe bubble. And this is because its retained in fat. Now our body has to repair its self from the variable damage opposed on it.
To put it bluntly, NITROGEN is hard to decompress from.
Now oxygen is a gas that we can displace some of that highle soluable nitrogen with, but we have some other issues with that. OXIDATION as well as the production and conversion of reactive oxygen species.
Oxygen seems to work in the fact that our body does need it (or some of it), its cheap compared to other gases and it is readily available throughout most of the world.
But now we're seeing a new trend building in the sport diving community. I know that you realize this because your diving it as I am, and thats Helium. Helium is not highly soluable like nitrogen, its none retentive like nitrogen and it has a benifit that oxygen doesn't. Its not an oxidizer. The reduction of narcosis is an added bonus.
Chris can say what he will but the proof is in the pudding. I think there's LSD in his. Just kidding Chris. But a diver really needs to listen to his/her body and pay particlar attention pre and post dive to their physiology. Its actually pretty easy.
There has been some extensive research in the last 10 of so years through the University of Southern Florida, the USN, Hamilton research, WKPP and others showing many problems with Nitrogen. Today we even use Helium to decompress with so that we do not continue to load slower tissues with a retentive gas.
I use to do a lot of nitrogen dives that would really load my tissues. I use to feel the effects such as fatique, sometimes extreme fatique. My limph glads would sometime swell. I often got sick after a big dive probably due to an alteration in my auto amune system from my body combating the assult on it from the nitrogen. This no longer happens even on more aggresive dives than I use to do.
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