(MiBand 5) Deep sleep times short to the point of unrealistic
Hi, y'all! I recently bought MiBand 5 (it's my first activity tracker ever). Overall I'm happy with it. The measurements seem reasonably accurate (including steps taken, heartbeat rate). It's not perfect at all times, but any errors in values seem minor, from what I can tell (for instance, the watch adds about 100 steps at night. I know I don't walk in my sleep, but the number is so minor compared to the actual number of steps per day, I don't mind).
One big exception is sleep pattern analysis. I understand that the sensors on the device can only do so much, and it's fine if there are *some* inaccuracies. For example, there are short times that register as awake when I'm almost certain I never woke up. And that's perfectly fine.
But the fact that three nights in a row now, the deep sleep time registers as less than 20 minutes is suspect, to say the least. The first night I slept really badly, so I thought this was the reason. But the two subsequent nights I had a pretty normal night's sleep, and the deep sleep still registers as a little over 15 minutes at the very beginning of the night. And I highly doubt I sleep for 6 to 8 hours without *ever* falling into deep sleep.
Is this something the device will "figure out" and calibrate to in time? Could there be something about the way I sleep that throws it off? Again - I don't expect extremely accurate results, but I don't think the measurement is even in the right ballpark, and that's extremely disappointing.
Posted Sep 4, 2020, 10:05 AM UTC
Same problem here and with everyone I know with a Mi Band 5. The deep sleep detection is just a joke. I had a Mi Band 2, 3 and 4 as well as several other brands of fitness trackers and all of them detected a deep sleep of 1 up to 3,5 hours per night that is absolutely normal. Mi Band 5 detects only 20-45 minutes, extremely rarely it may go up to 50 minutes. If I had so short deep sleep every night, I would be exhausted now, but instead I feel fine.
Regarding your question, no, it doesn’t calibrate with time, I have it for more than 2 months and I haven’t seen any improvement.
I even used my old Mi Band 4 and the new Mi Band 5 simultaneously the same nights (paired to different devices each, as it is impossible to have them active simultaneously on the same device). Mi Band 4 was still detecting 1-3 hours deep sleep and Mi Band 5 only 20-30 minutes. What a joke.
Others say that the problem is with the Mi Fit app when it is connected to a Mi Band 5, as other apps on Android (like “Sleep as Android”) detect the deep sleep phase correctly. I can’t test because I have an iPhone and Mi Fit is the only app available for it.
Others say that it is due to the REM detection, but REM is not a part of the deep sleep phase, so we shouldn’t add it to the deep sleep duration.
That actually sounds like good news in a roundabout way. If it's an issue with Mi Band 5 specifically, and it happens to many people, there's a chance it'll end up being removed relatively easily? Well, eventually.
It looks like only a software issue, so let’s hope it gets solved with a future update.