How Sleep Cycle Works

Waking up easy is all about timing. Sleep Cycle tracks your sleeping patterns and wakes you up during your lightest sleep phase, without a conventional alarm clock. Waking up during light sleep feels like waking up naturally rested.

How many sleep cycles per night?

The average sleep/wake cycle is five stages of sleep, with stages 1-2 as light sleep, 3-4 as deep sleep, and the fifth stage as REM (rapid eye movement) sleep.

  1. The first is light sleep and in this stage, you drift in and out of sleep. Your eyes move slowly, your muscle activity is slow, and you would be easy to wake up.
  2. In the second stage, your body starts preparing for deep sleep. Eye movements and brain waves slow down, your body temperature drops, and your heart rate slows down.
  3. Entering the third stage, you are now in deep sleep. Extremely slow brain waves called delta waves are intermixed with smaller, faster brain waves.
  4. In stage four, you stay in deep sleep and your brain almost exclusively produces the slow delta waves, guiding you towards the fifth stage.
  5. Entering the final, fifth stage, also called REM sleep. Now your eyes are closed but move rapidly from side-to-side, due to the intense dream and brain activity you go through in this stage.

Tracking your sleep/wake cycle

Your movements vary with each sleep stage. Sleep Cycle uses sound analysis to identify sleep states, tracking your movements in bed, and a wake-up phase (30 minutes by default) that ends at your desired alarm time. During this phase, Sleep Cycle will monitor signals from your body to wake you softly when you are in the lightest possible sleep stage (stage 1-2).

How to use Sleep Cycle

Sleep Cycle has two motion detection modes. You can change modes under Settings > Motion detection (if Alarm is turned On in Settings).

Device Placement

The built-in microphone is used to analyze your movements as you sleep. It’s important that you place your phone correctly:

Sleep Cycle phone placement


The accelerometer is used to analyze your movements as you sleep. It’s important that you place your phone correctly:

Sleep Cycle's accelerometer is used to analyze your movements as you sleep.

Depending on your type of bed and mattress you might find certain placements work better. Please do not place your phone underneath a pillow or thick mattress as it can become warm when charging. If you feel uncomfortable having a phone close to your head, you may set it to Flight Mode. As a bonus, this also ensures that no one can bother you while you sleep.


Snooze by simply double-tapping on the phone. Picking up the phone will also automatically snooze. Sleep Cycle has two snooze modes:

Intelligent snooze

Intelligent snooze lets you snooze through your wake up phase. Each snooze duration becomes shorter, gently bringing you from asleep to completely awake at your desired alarm time.

Regular snooze

Regular snooze lets you choose a specific snooze time between 1-20 minutes. You can snooze an unlimited number of times. You can change alarm clock modes under Settings. Snooze can also be completely disabled.

More information is available in our Sleep Cycle FAQ.