Posted by Maddiver on November 20, 2001 at 11:58:58:
In Reply to: MadD, so the "Im tired" feeling is subclinical DCS ? posted by Karl S. on November 20, 2001 at 10:41:52:
***I'm no decompression expert and don't claim to be either***
During Grad school I used to live right behind a frat house and every sat morining I'd have 8-10 guys banging on my door at 11 am to suck on 10 min of O2 through my regulator for $10 a pop and it made the difference between being 'green' all day and missing the noon game or being able-bodied and ready to party again. So the oxygen 'rush' does occur in oxygenating cells and providing fuel. The key in diving is that you have the increase PP02 and resulting decrease in PPN2, however bubbles are still moving into and out of solution with nitrox. Are there any experts on this list on cellular biomechanics and can describe the transference of bubbles of differing sizes and compositions through the cell wall without making me butcher the terminalogy? So you may have the first benefit of the 'oxygen' high but in my ***opinion*** it is the decreased M-values and resulting gradients that are created by use of Nitrox on air tables that leads to 'feeling better' comparatively. In other words you leave further 'padding' in place when looking at saturation rates for tissue compartments. This also adds a 'pad' for botched ascent rates as well because as I keep harping on its all about ascent/deco rates. Although there are cases of 'Oxygen Bends' where the metabolic gas actually bubbles and comes out of solution but this is beyond the scope of this discussion and the type of diving applications I think we are discussing here. Many of my own experiences with the 'I'm tired feeling' on air that turned the light on for me were on Drift Dives in Palm Beach where you get in go down to max depth of 60ish and do nothing the whole dive except drift (akin to cozumel) and these were after a full 8 hr sleep with no partying the night before and good hydration. the other element to this that hammered it home was that I was running track and cross country at the time and feel like I had a pretty good fitness level as a distance runner so the 'physical exhaustion' variable was out if the 6 ft 300+ lb guy behind me could hang the entire dive. More debatable observations: Also I would watch my buddy who wouldn't pony up the cash for nitrox or o2 and do the same profile and want to go to sleep right away when he got home....that one cost him a girlfriend real fast. Nitrogen is evil that way.