OK, I've read a lot about why we become SOB even if O2 saturation levels are at 90 or above.

I am a CO2 retainer and use purse lipped breathing when I exercise to get rid of as much of that nasty CO2 as I can.

But I still can't figure out if cranking my oxygen up when I exercise is harmful or even helpful.

I think I do better cranking it up so O2 stays at 95-97 but I don't have any way of really evaluating other than how it feels at the moment.

So can anyone tell me if it hurts to crank up the Oxygen?