Proteus Jones posted:

There's really a narrow slice that's considered normal.

Anything 95%+ is normal.
90-95% is monitor and let your doctor know.
Sustained <90% is get to the emergency room.

*Usually* when you dip down into the 80s, you'd feel a vague sense of suffocation due to CO2 imbalance, but COVID has thrown a spanner in the works there since it messes around with surfactant production in the lungs. In this case it fucks with O2 pickup but not CO2 elimination. So even though your lungs are getting damaged and working harder, none of the usual symptoms of pulmonary distress presented. People were showing up at ERs with 85% spO2 walking and talking one minute and getting hooked up to respirators the next.

This pulse oximeter for people considered at risk for COPD, COVID, or with cardiopulmonary disease is a godsend and another data point to collate for trending. I just had open heart surgery last year, so this means I can stop having to manually collect readings on a separate device 3 times a day. Now if only they could magic my BP readings I'd have the perfect medical device on my wrist (I do have a bluetooth BP machine tho). My cardio loves the watch since there is a wealth of trending data he grabs when we do our checkups.