How to use sleep data

[jrose1982]

The sleep tracking feature of my FitBit Charge is one of the reasons I finally decided to get one.

But as I learn more about how it works (and how it doesn't) I'm not convinced this feature is useful. Or perhaps I just can't figure out how to use this data.

First off, the FitBit does not actually measure sleep, it measures movement (or lack of).  I realize there is a relationship between sleep quality and movement, but by itself it does not tell the whole story. I've been looking for some guidance on how to intrepret this data.  I would love to find a study in which participants wore an accelerometer and some more reliable sleep study device to compare results, but I haven't found any such study.

Second, I can't figure out if I should be using Normal or Sensitive mode for tracking sleep. When I first got it, I used normal and my sleep efficiency was measured in the high 90's. But I was still tired all the time, so I changed it to sensitive.  Now my efficiency is measuring in the low 70's (sometimes lower).  Here's the kicker: About the time that I changed it, something happened in my life that has most definitely effected my sleep.  So I can't tell if my low score is because of that life event, or because of sensitive setting, or both (probably both).  It's also possible that my exhaustion can be caused by something other than poor sleep quality, so my decision to change to Sensitive on that basis alone might have not been correct.  I can't find any guidance on how to choose between Normal or Sensitive.  

And lastly, what do these results mean?  Sleep duration is controlled by two factors: the times I go to bed and wake up; and how restlessly I sleep.  The first are factors I can control.  But I'm more interested in my restlessness while I'm sleeping, which is probably best described with that sleep efficiency score. But what kind of sleep efficiency is normal?

Right now, the only value I can see in this data is to watch trends as I change the habits that affect sleep. Something I could have done without the FitBit (by scoring how tired I am everyday).

I've heard people say that it could clue you in to whether or not you need to see a doctor about sleep apnea. But I can't find any information on what to look for in your FitBit data that would support that conclusion.

[jrose1982]

I found a useful post on this topic, if anybody else is wondering about this:

http://www.huffingtonpost.com/dr-christopher-winter/sleep-tips_b_4792760.html

This was a self-test conducted by a sleep specialist.  He wore 5 different sleep trackers (including Fitbit Flex) during a polysomnogram and compared the results.  Very interesting.

[ButtercupBlue]

I saw a post the other day and you can change the sleep Option on past data between normal/sensative by clicking on the pencil at the top right of the sleep graph on the dashboard/webpage.

Sorry no help on the sleep data. Actually wondering what the "norm" for sleep is suppose to be.

[Shellz_AU]

I was sent for an in-home sleep study test last month. Lucky for me, my Fitbit Blaze arrived the same morning so I was able to compare it against the professional gadget with all the monitoring wires etc.

I got my test results back today and am still trying to compare them to the Blaze readings. But the efficiency is pretty close with using the Sensitive mode on my Blaze. 

Blaze gave me a 67% sleep efficiency and the professional sleep study came back as 72%. 

Blaze did say I woke 6 times, compared to 4 times of the professional one. 

I personally think the Fitbit Blaze (can't speak for the others as the Blaze is my first tracker) is pretty accurate at monitoring your sleep.....even if out just slightly. The 'normal' mode in my opinion is way off - at least was for me. It gives me near 100% efficiency and after learning my sleep issue today, I KNOW that is very incorrect!

If anyone else is achieving poor sleep efficiency - well below 90% on a regular basis, I highly recommend getting a sleep study done!