Sleep Cycle (iOS application)


Sleep Cycle (alarm clock) is the “Sports Tracker of the dreamworld”. I’ve been using this application more or less regularly for over 2 years now. I use it only when I’m sleeping alone and nowadays as a single on daily basis. The application has an Android version also. When I started using this app it had only a 1.99 $ version available. Today the basic version is free, but you can still find the paid version which offers e.g. better statistics.

This is how the app works. You put the phone face down between your pillow and sheet when going to bed. I use it so that I place my phone between the mattress and the mattress topper where it works just as well, but is more less likely to fall on the floor during movement at night. You have to also plug your phone to the charger or else this app will suck your battery dry.

The app uses the phone’s accelerometer to monitor your sleep. There’s also an option to use the phone’s microphone instead. In my own trials the microphone option didn’t seem to be any better or more accurate as advertised, so I’ve kept sticking my phone under the mattress. The accelerometer can unmistakably distinguish wheather you’ve just turned sides or been awake and risen out of bed.

The application’s own website tells us this of different stages / cycles of sleep:

While you sleep, you go through cycles of sleep states. The first state in a sleep cycle is light sleep, followed by deep sleep and a dream state referred to as REM-sleep. A full sleep cycle lasts about 90 minutes and is normally repeated several times each night.

Sleep Cycle will try to wake you up when you’re at light sleep if you use it’s own alarm clock. In example, if you set your wake up time for 8.00 – 8.30 the app could wake you up at 8.12 when noticing that you’re in an optimal stage in your sleep cycle. In any case you will be woken up at 8.30 by latest even if you would be in deep sleep. I’m not using this option anymore myself (I rely on iPhone’s own alarm clock).

Application’s views
  • 1. Main view for one night’s statistics
    • Here you can see your sleep “cycle” for your last slept night. You can see your dream’s different stages and an estimate of the quality of your sleep (my night was 99 %). The app keep a track of the time you went to sleep, when you woke up and time spend in bed total. In addition you can estimate your own “waking up sensation” with three different smileys and record your resting heart rate by measuring it with the phone’s flash and camera (I had 48 bpm). The app also reads (at least in iOS) :ssa) the amount of footsteps from Apple’s own Health -application.
  • 2. Weekly view showing amount of sleep
    • Here you can see how much you’ve slept daily during the past few weeks. These view in the “Trends” tab are highly interesting as you can compare your stats to worldwide database. For example, people in Finland slept in average 7 ½ hour nights when my average was ½ hour more during the same timespan. The shortest nights in average were measured in Saudi-Arabia and longest in New Zealand.
  • 3. Weekly view showing the quality of sleep
    • Here you can see your daily quality of sleep value during the past few weeks. You can compare your average to your country’s average value. In addition you can see where people sleep the best and where not (a 1:1 correlation can be detected in the previous view’s amount of sleep information).
  • 4. Weekly view showing your heart rate when waking up
    • Here you can see your resting heart rate development if you choose to measure it after you wake up. For me it’s natural to follow my resting heart rate data in long term as I collect heart rate data also when exercising. Besides it tells you something about your overall fitness. According to the stats people in Iceland are the chilliest bunch of all, at least when waking up. 😉


  • 5. Weekly view showing dialy footsteps and their correlation to sleep quality
    • This view combines the footstep data from Apple’s own Health app to the sleep quality data from Sleep Cycle. We can clearly say that the more you strain yourself physically the better you sleep – so move!
  • 6. View showing the quality and amount of sleep during different weekdays
    • This view shows the average sleep quality and amount of sleep for different weekdays. It isn’t a big surprise (to me at least) that I sleep worst on Sunday-Monday nights and best on Friday-Saturday.
  • 7. View showing the effects of atmospheric pressure and moon phases to sleep quality
    • Does the full moon keep you awake? Find it out! My long time statistics (~200 nights) tell me that I sleep best when the atmospheric pressure is high and it’s half moon. I sleep a little better than on average when it’s full moon and worst when it’s new moon.
  • 8. You can add your own notes of which the app builds statistics
    • Long walks and stressful days enhance sleep quality when short sleeping time and going very late in to bed reduce it (surprise surprise!).
Summa summarum

I warmly recommend getting acquainted  with this application if it raised interest in you. The app’s algorithms really work and the assessed sleep quality was right on par every time (gut feeling when comparing with your own sensation). The app won’t necessarily offer big “aha” moments and instead gives confirmation to things you already knew. The place where Sleep Cycle can really make a difference is in achieving motivation to change the things you know are eating away your sleep quality. It motivates in to action like Sports Tracker does for certain type of people (including me).