During sleep, our body goes through sleep stages which change each other every 90 minutes - fast and deep sleep. During deep sleep, the brain and body rest, the body restores its strength. And in the fast phase, we see dreams and the brain works even more actively than in the daytime.
Apps and gadgets track sleep stages and wake you up in the fast sleep phase when the body is most ready for awakening. The usual alarm clock rings exactly at the set time. The tracker catches the best time for awakening and helps you to wake up easily.
Tracking sleep helps to see what impacts on your sleep quality (training, overload, flights, alcohol, overeating, etc.) and how it affects your energy and stress level. Trackers help to understand whether you are sleep deprived and how good your schedule is.