RE: Positional apnea
As I've been saying for awhile, it isn't just us. Choral directors know that singing while looking down at the music cuts out volume and messes up your timbre. The gold standard is singing memorized, but for those of us old people, we get the constant reminders of "look up!" and "sing out!" and even the one I'm never sure what they mean, "raise your palatte!" We are taught to hold the book up and then sing out over the top, as singing hunched over kills the sound.
RE: Positional apnea
Glad to see the studies are finally catching up to what we have known for years, although a cohort of 28 participants in a very limited study, won't win the Nobel Prize for me.