There is nowhere that high in the UK apart from a few mountain tops so I don't really get to experience altitude unless I go skiing in the Alps and I have not really noticed a big difference there. It might affect me more if I were running hard. I know a lot of athletes train at altitude to improve their breathing.

At parkrun today I could feel myself gasping for air, but then I did my best time in a while. We need that oxygen. I've seen stuff about just breathing through your nose, but I struggle with that when running. I will never be an elite athlete, but I will look out for where I can make small gains.