A new one for me???
Steve, I know a lot of people who experience similar issues at altitude including myself. Apnea essentially prevents the lungs from filling with air which is agrevated at altitude. In a nutshell a CPAP is a great fix. There are units available with battery power. I just use a quiet inverter generator. I live at 1100' and hunt at 6400'-8300', that can have you gasping for a few days.