For newcomers to this blog, the Zeo works by analysing your actual brainwaves (like a single channel EEG) while the FitBit is a small accelerometer-based device that detects movement (you move differently, or not at all, when you are asleep).I’ve been using my FitBit Ultra a lot lately, and have generally been impressed by the overall accuracy of the device. So the other night I put the Zeo Sleep Manager back on my head, the FitBit Ultra on the wrist of my non-dominant arm, and went to sleep …. well, not really sleep as you can tell. This my opinion of one versus the other.
Here are the graphs produced by the two for the same night:
It’s easy to see why my personal preference is the Zeo, although the FitBit is much less intrusive. The data you get from FitBit is nowhere near as detailed, and if I take the Zeo to be the more accurate* of the two, the accelerometer-based FitBit could be considered a “rough guage” of your night – while Zeo is a “detailed analysis”.
Note that Zeo says I slept 6:04 and FitBit says 4:50. That’s quite a difference. Note that I put the Zeo on my head for about an hour before actually turning off the lights, while I activated FitBit as the lights went out.
*In measurement, accuracy is more important than precision, so I am assuming that Zeo is both more accurate and more precise. Imagine your speedometer telling you that you’re travelling at 45.678mph (precise), but in reality you were going 55mph (accurate).
When I’ve had a “bad night” with the Zeo, I know it in the morning without looking at the measured results. I can now tell you +/- 5 ZQ points what kind of night I’ve had. I always find the results of the FitBit more uplifting because I think it “under-measures” actual night-time awakenings (which is my big problem – awakening 10 – 15 times per night).There is another phenomenon going on here that nobody ever talks about – the observer-expectancy effect. This is where the knowledge that you are being observed (even by something as inanimate as a Zeo or a FitBit) actually affects the outcome of the experiment. This is becoming more clear to me as time progresses – and it seems more apparent with the Zeo than with the FitBit (the Zeo being slightly more intrusive).
The observer-expectancy effect comes in on those nights where I do not wear a device. I sleep better. Whether this is all purely in my head I don’t know, but I really do feel that I get a better quality sleep when I don’t measure it.