Because a picture is worth a thousand words, and, honestly, because I am feeling too tired to do much of a write up on anything today… The sleep graphs from last night, starting with the fitbit.
Fitbit Graph for 10-27-2010
And now the Zeo:
Zeo Graph from 10-27-2010
They’re pretty close on the amount of sleep; 12 minutes difference isn’t that much. And they match up on that 6 am waking. Sleep onset, they’re 8 minutes off of each other (I put the fitbit on two minutes after the Zeo, so it isn’t actually a ten minute gap). But, if you notice the movement shortly after sleep onset on the fitbit graph, it actually probably does match up. I just managed to lie still for a few minutes, which it’s interpreting as sleep onset.
The fitbit thinks I had several small wakings that the Zeo doesn’t register, and my own recollection agrees with the fitbit. However, Zeo tells you in their documentation that a waking has to last a certain amount of time in order to register. With the fitbit, all I have to do is twitch*. So that’s a difference in mechanism. I wouldn’t be surprised if you got similar results between an actigraph and an EEG in a sleep lab. But then, that’s why sleep labs use multiple measurement systems. It’s the cumulative data that gives you the whole picture.
Beyond that, the Zeo marks deep vs light vs REM sleep, which the fitbit can’t do (and doesn’t pretend to).
Thus far, both devices are living up to their promises.
*It is worth noting that a small twitch is not necessarily a full arousal. We tend not to move while sleeping, but that doesn’t mean we don’t move at all.
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I’m actually about to do a similar experiment, though I’m also going to video myself to see how many of the twitches are picked up by the fitbit. I also just discovered that you can set the fitbit to normal vs sensitive mode during sleep. It’s in the preferences.
I’d definitely trust the Zeo over the FitBit for sleep latency.
By the way, I’d love to see you do a couple of nights with vs without the CPAP to see how it affects movement as picked up by the FitBit.
I’ll definitely do a comparison 🙂 I’m currently without CPAP, following the turbinate reduction. I’m allowed to start using it again on Tuesday. Which will also be the first time I’m using it since I started using the Zeo.
I tried setting the fitbit to sensitive, and found that it was overly so. There was no way I was moving as much as it appeared to think I was. I suspect it was picking up on Jason’s movements exaggerated out by the water bed.
I’m curious to see the video/fitbit correlation.
You sleep on a waterbed with another person? No wonder you don’t sleep so well. Your BF may not be up for this, but you should compare your sleep quality alone vs with him in the bed as well.
Yeah, I’m becoming more and more convinced the waterbed is a problem.
We’re in negotiations at the moment about changing our sleeping arrangements.
Great website! Did you compare the sleep quality data of the two over time?