I am a reasonable sleeper, both in terms of the quality and the quality of the sleep I get. They say that you need at least eight hours of sleep a day on average and I tend to believe it. But I am not an early or a late raiser as well (some time around 7 - 8 am). So just as much as the amount of sleep I get, the way I wake up is as important to me as I am not too much of a morning person. Before I had the Sleep Cycle App, I used to wake up around the same time using the standard alarm clock, fixed at a particular time. However there was a 50% probability for me as to how the day went, i.e., I was either energetic or groggy the whole day. In fact I could see a pattern of this occurring almost alternatively. So when I first heard about the Sleep Cycle App, I was curious to see how it would help me.
I did some basic research on different stages of sleep and found a little bit more than the usual of not to drink coffee after 2 or 3pm, not to sleep at different times every day, not to stare at a bright screen (smartphone) too much in dark in bed just before going to sleep, etc. The Sleep Doctor (via the CNET's 404 show) was really helpful in this learning process. Sleep has another aspect to it and it is its quality. I found out about REM cycles and how you don't want to be woken up when you are in one of your REM cycle or else you would have a bad (groggy) day, etc. So far, all this science and has a good amount of backing to it. So in summary what I found was that you want to wake up when you are at the lightest (in terms of intensity) mode of sleep, for the best experience, for that day. And Sleep Cycle claims to do exactly that. How well it does what it claims, read more to find out.
Before I begin my review, let me tell you that this is probably the most any reviewer out there would have used an App before reviewing it, I have a total of 561 nights logged in my Sleep Cycle App as of today! So my experience here is quite exhaustive. You can set a time for the App to wake you up, but unlike other alarms, Sleep Cycle can wake you up any time before the time you set the alarm to, with a 30 minute window (this window can be adjusted in the settings), when it decides that you are at the lightest mode of your sleep. There is a dedicated section explaining how to place your iPhone at the right area around where you sleep. A couple of important points about the placement is to have the iPhone plugged in to the charger and keep it near your pillow, neither too close nor too far. The App should be able to sense your movements (using the iPhone's inbuilt sensors), as in how much you toss and turn in your sleep to determine which stage of the sleep cycle you are in, to work effectively. And from my experience following the placement instructions described in the App works the best.
Settings options in the App include, things like modifying wake up phase time, sound of the alarm, turn off alarms only during weekends (but still monitor sleep - this one is my favorite option), adjusting snooze periods, etc. Analyzing sleep data is also simple and straightforward. As seen above, I have shown my worst and best night of sleep, to enhance the point. The best night of sleep has multiple peaks and valleys that are pretty stark in their height difference, meaning I went in and out of REM cycles multiple time (around 4) that night, that is good and I woke up (by the alarm) literally when I was already waking up (according to my brain). The worst night of sleep had only only REM cycle and I woke up (by the alarm) when I my brain was going into a deep sleep and that is bad. This panel also shows average stats of the sleep quality, like the average time in bed (mine is just under 8 hours!), shortest, longest, best and worst nights of sleep.
Tilting the screen to a landscape mode, triggers a "graphics" mode with more detailed plots like sleep quality, sleep time, etc. over different periods of time. These plots, for me have been extremely useful in trying to understand my sleep. For example, during the winter time in the Bay area I tend to go to bed later than during Fall, I don't know why... Then things like my sleep quality has been going down lately, I go to bed late on a Friday or Saturday, I sleep the best on a Sunday, etc. These all are extremely useful to me and I can make sense of these trends, correlating them to my lifestyle.
With the recent introduction of iOS 8, Sleep Cycle was quick to update its App to integrate with Apple's Health App. Once you go into the sources screen in the Health App, there will be an option for Sleep Cycle, where you can select how Sleep Cycle interacts with the Health App. Selections can be made on both Sleep Cycle writing data in to the Health App and reading form it. The integration in my experience has been seamless so far.
Another recent update to the App has been to include heart rate monitoring using the iPhone's camera. I am not sure about the accuracy of this measurement, particularly when it uses the camera(!) and I haven't had time to explore this feature, as it was introduced fairly recently. It is interesting to note that the App prompts me everyday after I wake up (right after I turn off the alarm) for a heart rate measurement and not any other time.
Though a lot of what this App does, does not seem straightforward and is easy to dismiss as another gimmick, in my experience this App is no gimmick and that is the reason I have been using this App for almost two years now (remember the 561 nights of sleep data that I have logged in). This App does one thing and one very simple thing, based on how much you toss and turn (to determine the intensity of your sleep) using the iPhone's sensors, wakes you up when you are least asleep. I have found this App to be extremely useful. My sleep schedule has become more consistent and I now understand the way my lifestyle affects my sleep and vice versa. The App costs $0.99 in the App store and has a premium, in-App purchase, where for a dollar or two (per year), you get secure back up of your data (other than the iCloud back up that is inbuilt), web access of your sleep data, etc. If you are in the market for an Alarm App or you want to understand your sleeping pattern better and/or improve your sleep quality, this App is definitely worth a try and I recommend it highly.