I've had sleep apnea for many years, breathing strips sold at any drug store would greatly improve oxygen while you sleep.

I'm not one that would sleep comfortably with a CPAP machine or mouth pieces, so this is a good alternative for aiding sleep apnea problems.

I have used them for years, around 10 dollars a month if you buy the store brand. I think they are almost as effective as a CPAP but your results may vary.