Hi! I've recently been checking my pulse etc on a pulse oximetre and noticed that my sPo2 is rather low. My pulse usually lies aroun 50-60 but my spo2 can go below 80 and I don't notice at all. I'm not breathless, or feel like I'm struggling for breath. I sometimes notice being really lightheaded and when I check my my o2 is very low (below 80). But it can hovering mid 80's-90's and then go up to 97 and then within a few mins back down again. I thought the machine might be faulty so have tried on a few others too and have got the same result. And I don't have nail varnish on or anything like that. Could this be anything to do with chiari? And what could my doctor do about it? Thanks