Have you ever gotten out of bed feeling horrible? If yes, it’s probably because your current alarm clock doesn’t care how you feel. You can change that with one download. The app Sleep Cycle is the most advanced alarm app on the App Store. Sleep Cycle tracks your sleep night after night, recording your sleep data and graphing it to allow you to compare a night’s sleep with another.

The alarm feature of the app is probably my favorite part. After using it for a few months, I’ve realized I wake up feeling less tired when using the alarm. This is thanks to the accelerometer in my phone. With the phone sitting on the bed, the accelerometer senses the movement of the user as they sleep and determines the type of sleep they experience.

There are three major types of sleep that Sleep Cycle determines: light, deep and REM (dream state). By measuring movement, the app determines what state the person is in and wakes them up at the appropriate time. This is Sleep Cycle’s claim to fame. By knowing the patterns of sleep, it can wake up the user in the lightest sleep possible, therefore creating the ideal “wake-up.”

The way that Sleep Cycle achieves this is by slowly waking up a person with quiet noises and vibrations. This slowly transfers the user into a light sleep in order to not feel groggy when they wake up. The transfer may take some time, so the app recommends a 30 minute window for the alarm to wake you, but it is possible to shorten or lengthen based on your preferations.

Sleep Cycle is an app I use on a nightly basis, not so much for the statistics, but for the alarm. Waking up feeling fresh and awake may be the difference needed to arrive at school without feeling like you are going to pass out.