Review: TDI Normoxic Trimix with John Chatterton, November 2019

[wetb4igetinthewater]

I thought it was common knowledge that rapid descents on air to significant depths increases the severity of narcosis?

I know people who ride a scooter (and are consequently not exerting themselves by swimming down hard) and they STILL need to descend much slower than they can equalize if they want to avoid too much narcosis.

Is it documented anywhere? The only thing I know about descending fast is HPNS, but that's beyond depths beyond 100 meters (according to my Google search results just now).

I'm not an expert tech diver however. Still, I'd like to learn where this is documented.

 

[Degenerate]

I snorted when I read this - good stuff!

They are still popular even if the GUE crowd bangs on them and the price (at least on this side of the pond) makes you faint. Plus getting good parts & service is a pita. If I dove in Swedish water temps more (uff its cold there!) I would seriously consider switching.​

It's not so bad here in Sweden, we had 3 degrees celsius in the water last week, warm and cozy!
While Poseidon regs are probably more common here than elsewhere for obvious reasons, they are still expensive as hell.

 

[LandonL]

I thought it was common knowledge that rapid descents on air to significant depths increases the severity of narcosis?

I know people who ride a scooter (and are consequently not exerting themselves by swimming down hard) and they STILL need to descend much slower than they can equalize if they want to avoid too much narcosis.

I have never heard of it being 'common knowledge'. The trouble is that measuring narcosis empirically isn't really possible, as it is a subjective effect. The likely scenario is that the rapid onset is more noticeable than an insidious onset by a slower descent. The result is the same.

Is it documented anywhere?......
I'm not an expert tech diver however. Still, I'd like to learn where this is documented.

I know of no studies that have analyzed or measured descent rate in relation to narcosis. Likely because of the difficulty in doing such a study directly and quantitatively. This is more likely the result of tech divers and/or instructors making assumptions than being based in any scientific principle or study.