How accurate is sleep on Versa 3?

[salilsurendran]

For some reason even on days and weeks when I sleep really well fitbit always reports that I only slept for 6-7 hours. Recently I was on vacation for a month and was sleeping the whole time and it just recorded 8 hours of sleep 5 times?

[RiekoC]

Fitbit trackers use movement, heart rate, heart rate variability, respiratory rate, and blood oxygen levels to give you an idea of how much time you spent asleep each night. 

I often wake up early in the morning and will lie in bed without moving, which Fitbit will track as Light sleep or REM. In some of my sleep graphs, there will be periods showing I was awake, although I don't remember waking up around that time. Apparently, I was moving around in my sleep enough for my Fitbit to log it as being awake. 

For me, sleep tracking is interesting information. But knowing that I can "fool" my tracker, I don't rely on the values. Instead, it's more important to me on how rested I feel. 

The Qualified Scientist YouTube channel is one that you might want to check out. He is a scientist and uses various equipment and methods to evaluate the accuracy of popular wearables. Although he has a video where he evaluated the Versa 4, there isn't one for the Versa 3. He did find the Versa 4 good for sleep tracking.