I acquired a Garmin Fenix 6X a few months ago and one of the new metrics it provides is a pulse oximeter reading. Mine consistently reads in the range 91-96%. I live in London (at sea level) so this seems quite suboptimal. Question for other Garmin users with this feature- do you trust the result? do you measure consistently boringly high (as you should expect)? have you used at altitude (at the least I would expect it work relative to itself)? should I pay any attention to this at all?
I have tried measuring two other people- one measured what I would consider normal at 98%, and one who had fairly recently recovered from a confirmed case of COVID at 91%. I have not knowingly had COVID but did have a mystery respiratory illness in early January 2020. Lastly a few years ago know I did have a lowish haematocrit reading (~37ish I think) and was recommended to supplement with iron which I have done since.
I feel that my running performance is down a considerable amount compared to previous years- but in the year before buying the new Garmin, I only ran untracked, so don't have any training metrics to show I wasn't just lazier than ever before, or that the drop off was specifically after January illness (I definitely took a good few weeks off doing any aerobic work at all). My "I'm not lazy, but my physiology knowledge isnt great" hypothesis says my lungs were somewhat damaged by the illness and have never fully recovered, or I am still somewhat anaemic. Any thoughts from the runners of UKC? I don't really feel I can ask a GP about this kind of thing right now, it doesnt seem that important, but maybe should stretch to paying for a blood test.