When I am out doing my walking exercise and I have my oxygen concentrator with me, I have it at a setting of 2, I try and do purse lip breathing, but it seems like when I do that I am breathing really fast like I am not getting enough oxygen, but here's the thing, if I inhale and exhale through my nose it is not bad at all I can control my breathing better. What is the proper way to breath when you are exercising? and should I get a pulse oximeter to monitor my Sp02 levels, hate to spend all that money on a device that might not be that accurate.