HRV and SPO2 accuracy on Sense?

[hawaiichica]

Just got Sense. The resting heart rate measurement seems accurate at rest, however I have concerns about the accuracy of the HRV and SPO2. For SPO2, I have a separate Pulse Oximeter. When compared, the Sense reading is always a bit lower. So far, the HRV result I've gotten is very low. Considering the averages for my age and my overall health, this seems very off, and I will be testing HRV on another device. Has anyone else noticed these issues?

Moderator edit: updated subject for clarity and label.

[kathyl54]

Same here. If I have a very restless night and don't sleep very long I
don't get a reading.

[AlanSmitheeFB]

I do not know as I am not medically knowledgeable. There is advice in
Fitbit on when you should consider consulting a doctor so go with that

[SMDprofile]

Apparently the spo2 Fitbit is lower than an oximeter because it’s on your wrist and not your finger and it’s taken at night. So basically the reading is useless. 

[thomaslknapp]

Three years later, Versa 4:

I get an SPO2 average that's not just below the "at this moment" results I typically see from a finger clamp pulse oximeter (and had on a pulmonary function test at the hospital a couple of months ago), but well below what my previous fitness tracker (Amazfit Band 5) reported right up to the day I put it in a drawer and put on my new Fitbit.

As in: With the Amazfit, average SPO2 of 98%; Versa 4, 93 to 95% over the first week of readings.

My HRV also shows in the somewhat scary low range, but I don't have past results to compare that to.