If air wasn't a problem, how far could a human dive underwater without protection from the pressure?

Question

And aside from ears, what would begin to feel the effects of the pressure first?

Answer 1

your ears would stop you so it dosent matter - unless you dont have ears.

Answer 2

Sheck Exley made it to 400 ft. on compressed air.  There are a lot of factors other than the limitation of the air supply: the concentration of oxygen in air becomes toxic past a certain depth, nitrogen in air muddles the mind at depth, it takes more work to breathe at deeper depths.  As long as you can equalize your ears, pressure in your head won't be an issue.  I don't think an absolute maximum depth has ever been found.

Answer 3

The record at the moment is beyond 1000ft. If the toxic effect of various gases were not a problem to the human body and you could get many gases (and lots of them) that were safe then the limit is unknown by divers or doctors.

Ears do not present a problem as they are easy to "equalise". You can add air to them in a similar fashion to descending in an airplane.