spo2 accuracy

[SMDprofile]

My Fitbit sense 2 is showing 92/93/94 for a couple of weeks so I went to the doctor. 

Reading taken by doctor is 99%. 

False alarm. Thanks Fitbit for wasting my money. Moving to Apple after 7 years with Fitbit. 

[LZeeW · Accepted solution]

@SMDprofile   My background is human physiology and I have some insight for you.  Your Fitbit is reporting an average sleeping SpO2 and that is very different from your wide awake, sitting upright SpO2.  Everyone's sleeping SpO2 is lower than their wide awake SpO2.  You can have obstructive sleep apnea, but your wide awake SpO2 will be normal.

[SMDprofile]

Thaks for that. Any idea what the average drop over night is? 

I don't have apnea as far as I know. I do have mild asthma/touch of bronchitis that I generally don't need to treat, apart from an inhaler for a month every few years, if I go to the doctor.  A b it of sea air in the better weather usually clears it. 

[Rich_Laue]

I'm not sure what the average drop may be but while at rest, your body will not need as much O2 allowing the lungs to also rest a little. 

We have been asking for the option to have a real time Sp02 reading, but.... 

[LZeeW]

@SMDprofile   The reported low normal value seems to hover around 95%.  You mention leaving Fitbit and getting an Apple watch, but don't jump ship just yet.  Wearable SpO2 is measure two ways, by reflecting light on your skin or transmitting light through the skin.  Both Fitbit and Apple use reflected light.  There is more error in reflected light, especially when measured over hours.  You move your wrist in your sleep and you can lose a good signal.  I haven't used an Apple Watch, but I suspect you will get similar results.