[elric]

Oxygen saturation is something of a red herring when it comes to sleep apnea diagnosis. Sure, having significant desaturation (<85%) is not good for you. But what will really wreck you is the arousals. Someone here mentioned an AHI of 70, that doesn't just mean you're not breathing right seventy times per hour, it also means you're waking up seventy times per hour. With that many arousals, your saturation might not budge all that much, but you're basically not getting any sleep at all.

And while we're on the subject, AHI is also pretty terrible. You could have an AHI of say, 5, which means "you don't have sleep apnea", but if you're sleeping 8 hours and these events only occur during the 2 hours of REM, then you've got an AHI of 20 during REM sleep, which will still wreck you.