IANAD. I would point out the amount of CO2 that you breath out is far lower than any O2 concentration. Hence, O2 content in your exhale is not much affected. Be

IANAD. I would point out the amount of CO2 that you breath out is far lower than any O2 concentration. Hence, O2 content in your exhale is not much affected. Being in a well ventilated space may have a larger effect. I know people (with ALS) that nevertheless liked the higher oxygen, might be personal. Or because you need to breath less, effectively reducing your passive energy need. Anyways, your body needs a reason to burn those extra calories. Better consult a doctor though, oxygen poisoning is real.