I pretty definitely can't breath through my nose as well as I should be able to (deviated septum), and have been wondering for a while how much this actually impacts me. What was your experience like?
I do have a fitness watch though that can (supposedly) measure SpO2, and while that showed the occasional dip, it seemed more like a measurement error, and generally the values were in the normal range.
I also have had a finger pulse oximeter which logs and exports to an app via USB. If I sleep with that on it seems to be very reliable at recording the levels, the data certainly looks good and feels much more reliable than the Sense.
I have somewhat of a deviated septum, and even had surgery done half a year ago, but it didn't really change much unfortunately. I always need >=9 hours of sleep to feel good. I've slept on average 7 hours the past 2 weeks & I feel horrible (completely different reason for the reduced sleep). I did a sleep study a few years ago because I suspected sleep apnea, but because of anxiety or sleeping in a new place, I only ended up sleeping 1-2 hours that night. They didn't find anything, but I wonder if I should try again.
I have headaches but they are related to other sinus issues, though the doctor seems to think the CPAP should help. I’m not so sure but open to the possibility!
A few weeks ago, I tried Nasal Strips again, and for some reason, they are helping now and the difference is like day and night. I can only assume that it's because I got older and my life style changed, including nutrition, which was really bad when I was young. So dry mucous had too much effect for me to notice the benefits of the nasal strips or it's really just the bigger size of my nose :P
But the biggest change, compared to my young years, is that I am much more resilient to unhealthy stress and not continuously stressed as I was back then, when I was also regularly exposed to stress amplifications without time to recover.
And being able to breathe properly through my nose now amplifies everything for the much much better: mood, psychological resilience, performance --both cognitive and athletic-- time to fall asleep, sleep, with the latter two coming with their own boosts for the next day.
Most notable was the effect on my facial muscles. With the loss of those specific tensions came a direct effect on focus and concentration and self-control, which is all, to a great extent, mediated by the prefrontal cortex.