Answer: i had mine done and when i was at my worst, i could fall asleep standing on my head, so the wires were a cakewalk. they measure your blood oxygen level. mine dropped to just above 50% in an hour or two then they woke me up. then they fit me for a c pap mask then(they should have done this BEFORE i went to sleep,but anyway i was scary as h*ll for the 1st 2 weeks with my cpap bc thats alot of air blowing into your nose and i used to wake up daze feeling like a hurricane was going across my face. but after the 2 wks, i slept sooooo soundly i wouldnt move all night, i swear. from waking up every 20 minutes to sleeping all night and not moving was almost like being reborn again. its been 8 yrs for me now and my little cpap machine has seen every vacation, every hospital stay or every nap for that matter in that time. dont be afraid to0 be checked. it just might save your life, it did mine