Medically speaking it doesn't take very long for parts of the body to start turning blue such as the lips our around the mouth with just decrease in oxygen levels in the body. I work with babies and when they have oxygenation issues they can turn "blue" (actually more of a dusky color) in less than 30 seconds. I'm sure it takes longer in adults but I don't work with adults. I would be willing to guess in a matter of 3-5 minutes an adult would have a geleralized dusky appearance.
I can't exactly put a number on it, but its pretty fast. If you watch a SPo2 meter it takes a bit of time to drop past 90% and then it goes downhill fast. I wouldn't expect someone to maintain color with no air moving for more than a few minutes.
I don't think the answer would matter if your'e going to try this, you would probably be dead and when we find you, you would be blue.
I hope he was okay!
I don't know the answer to that question. USually people turn blue when the blood circulation slows down, depriving the body of oxygen. With somebody holding their breath they could only live for 4 minutes.
I heard 11 minutes.