This comparison isn’t going to be precisely fair, since I’ve been using my fitbit for about 10 months, and I only used Sleep Cycle (an iPhone app) for one night. But I can definitely give some initial impressions.
I’ve already talked about how useful I find the information from my fitbit. Here’s the data from last night, and no, I’m not sure what I was doing up at 2:41; I was on Ambien and it seemed like a good idea at the time:
Here is that same night, from Sleep Cycle:
Like the fitbit, Sleep Cycle uses an actigraph to track your movement during sleep. In this case, the actigraph is in your iPhone. You put it on the bed near you (the instructions recommended putting it near, but not under, my pillow. The theory here is that when you move, the mattress will reflect your movement, the actigraph will detect that, and the app will record the data. Plus, in this case, the app will choose when is best to wake you in the morning based on your sleep patterns. So, it has a slightly different purpose than the fitbit.
You can see, if you look closely, that the two graphs are pretty similar. The fitbit is literally just tracking movements. Sleep Cycle is interpreting those movements and correlating them with sleep phases.
Truth to tell, I’m not sure how accurate that part is. Actigraphs are valuable tools for sleep tracking, but they aren’t actually tracking brain activity. For that, you either need an EEG at a sleep lab or something like the Zeo, which monitors brain function. (You know I so totally want one of those. Besides, doesn’t she look like Wonder Woman, wearing that headband?)
I know people definitely move differently during particular phases of sleep, and I can see the correlation there. But… while I’ll buy that Sleep Cycle can tell me when I’m not dreaming (since we don’t move during REM) I don’t buy that it can tell me for sure that I am dreaming just because I’m lying still. Regardless, it’s useful information.
The two disagree a bit as to how much sleep I actually got, but only by ten minutes (Sleep Cycle gives me ten minutes more than the fitbit does).
I really like the alarm clock function of Sleep Cycle. We know that when someone wakes up from stage 3 or stage 4 sleep, they’re disoriented and groggy. And tired all day. A normal alarm clock can’t tell when you’re in those stages, so it can’t very well accommodate them. This is why I had a dawn simulator alarm clock for a long time (it’s broken now, which makes me sad). And, while I noted earlier that I didn’t think Sleep Cycle could tell me when I was dreaming or in deep sleep, I’m pretty sure it can figure out times when I’m definitely not in deep sleep.
I don’t yet have long term data from Sleep Cycle, so I can’t compare that function.
All things considered, not bad. For me, it’s kind of redundant since I already have a fitbit. Plus, I share my bed with my boyfriend, which means that I’m not the only one moving around (of course, it could well be that his movements wake me so that might still be useful). And we have a waterbed. Which moves a lot more, and a lot longer, than a regular mattress. I could easily see Sleep Cycle overestimating my restlessness. Which is less of a problem than the reverse would be.
Cost wise, fitbit is $99 with a mostly free website (there are some premium features, but I’m not interested in them at the moment).
Sleep Cycle is $0.99. That’s a huuuuuge price difference. Although, if you count the cost of the iPhone (or iPod touch), that’s a lot more. If you already have an iPhone, or have other reasons for getting one, it’s a great idea.
If, however, you just want to track your sleep, the fitbit is a better deal. Of course, I’ll probably use both; the more data the better!