I'd started wearing my O2 monitor when exercising, with the alarm set at 90% - which has proved useful to remind me to continue to breath appropriately at times I don't seem naturally inclined to - heading into terrain with higher athletic requirements bending over to futz with bindings, or topping a hill and stopping to crouch and take a steady photo.
And a few nights ago, I forgot to turn the alarm off, and have found it buzzing some nights.. which prompts me to breathe more deeply. Here's some charts from last night, in which it went offer several times - in the 2nd chart, I'm just about to fall asleep when it went off (the first CA). I was on my right side. The O2 monitor shows movement just before, I'd probably just rolled over. The O2 also dipped slightly in response to the second CA, but not below 90 - the "OA" did trigger the alarm again. O2 heading into this was 93%, just below my average these days of 95. My breathing just seems to taper off to being too shallow at times - my sensations through this is just one of relaxing.
The next chart shows a typical PB outcome, where the troughs are getting flagged as events - the O2 chart looks the same as the tidal volume chart - but I went into with relatively high O2 levels and so as a result the dips were only to 94% or so.
Not sure what to make of all this, I'm thinking I might give a soft cervical collar a try just to see if that helps any.