It varies heavily from person to person. People often don't have a terribly good sense of their own impairment until they have done some kind of task loading.
I used to say that I didn't feel narcosis until about 140 odd feet, but once when I was diving in Europe I had to convert my remaining gas in PSI to Bar using mental arithmetic. At the surface I have no problem, but I really, really struggled with it at 120 feet.
At 190 feet I have done things that I later had absolutely no recollection of.
When highly experienced tec divers like Gary Gentile and Brett Gilliam say that they are virtually fully functional at 250 feet on air, I believe them. I have seen air force pilots who can do 10 shots of tequila and then still fly a fighter jet (well, in a simulator...), so I have no problem believing that people's physical and mental dexterity varies as much with impairment as without.
I used to say that I didn't feel narcosis until about 140 odd feet, but once when I was diving in Europe I had to convert my remaining gas in PSI to Bar using mental arithmetic. At the surface I have no problem, but I really, really struggled with it at 120 feet.
At 190 feet I have done things that I later had absolutely no recollection of.
When highly experienced tec divers like Gary Gentile and Brett Gilliam say that they are virtually fully functional at 250 feet on air, I believe them. I have seen air force pilots who can do 10 shots of tequila and then still fly a fighter jet (well, in a simulator...), so I have no problem believing that people's physical and mental dexterity varies as much with impairment as without.