COPD is a heck of a disease. When I worked in cardiopulmonary rehabilitation, there were a few people with COPD that had some endurance but the majority of patients had very minimal musculoskeletal endurance in addition to their poor cardiopulmonary endurance. I'm impressed by this guy. I don't know if he'd have to get a TUE for Ironman races in order to use his oxygen concentrator but he'd easily be able to get one.