Hypoxia?

Well apparently an overnight oximetry monitoring report came back with poor readings.  This lead my doctor to order a sleep study for me.  My question is, how is a sleep study going to help when we've briefly checked my O2 sat levels during the day at rest & at exercise & they've been in the mid 80s.  Plus these sleep studies are expensive.  The other objection is my husband sleeps with one already, it took quite a bit just to get use to him having one, & I have to wear ear plugs.  Back in the ugly primal days of smoke signals & no technology I wore braces.  I actually could pick up radio signals or at least block them unless I sat in the correct spot in my room.  I had the dreaded head gear- I can tell you that I ripped in off in my sleep unknowingly nearly every night.  I don't see how this set up would be much better or much different.  Also, what about me still having low rates during the day when I'm not sleeping.  Mind you, I am much like a hybernating bear & love to be in bed as much as possible but....I'm just curious.  So, seeking answers I write to you all, what the heck is hypoxia & what is done for it?  My web searches have led me to many articles about sea diving or doing loopty-loops at high altitudes but I am not in the air force nor the navy nor do I partake in these activities.  I do live at a fairly high altitude but....that's about it.  I've never smoked but my father was a heavy smoker & died of emphasema, boy was that an ugly death.  Anyway, I'm super tired all the time & I'm very curious for some answers if anyone has some.   Thank you!