I posted this here since most folks don't look into the medical threads much. Recently I started flying a twin again and with that comes a little higher altitudes. My typical cruise altitude in the Cherokee 6 was around 7500'. I am now flying routinely at 9500' so I figured that I would buy a cheap pulse oximeter from Amazon just to see what my O2 saturations looked like. WOW! As a Floridian, at sea level my O2 sats are 98% or so with a pulse rate of 66. At 7500' my O2 sats are 94% and the pulse is 88. When I get up to 9500' my O2 sat drops to 89% with a pulse rate of around 100. I'm reasonably healthy with no meds... Not sure what is normal but this was an eye opener for sure!