Originally Posted by
DAa Aquamaster
I agree it helps an individual diver, but that's only part of the potential problem in setting solid END limits.
For example lets take the "average" cave diver has an "average" IQ. The mean IQ is 100 and the standard deviation for most IQ scores is about 15 points, so the "average" range for IQ is 85 to 115 and about 2/3rds of the population will fall within that range - with half of them being below 100 and half of them being above 100, but all of them considered (broadly) to be of "average" intelligence.
The point being a diver on the low end of that range is potentially 30 points behind a diver at the upper end of that range in terms of overall cognitive functioning even before we descend. Various subtest scores involving such things as spatial relations or numeric operations will have similar variation so the total picture is a bit more complicated, but you get the idea.
Do we want to have a different END based on surface cognitive functioning? Of course not - as the average diver probably does not know where they fall in temrs of general IQ let alone in subtest performance. But the first point is that most divers potentially have the ability to make informed decisions about the depth and conditions at which the really need a reduction in narcosis to function effectively and that makes more sense than relying on a flat 100' END.
The second point is that if a diver happens to be one with an 85 IQ, he or she is already challenged at the start of the dive and while helium might help limit the additional impiarment that results, it may not help him or her enough to "catch up" at the 100-150' depths we are talking about here.
The concern is what happens when the use of helium breeds over confidence because the person is using helium. At best, they are no better than they are on their best day at 10' and for some, that is just not all that great.
