What is a sleep cycle?
What is a sleep cycle? During the night you move between non-REM sleep, which runs from light to deep, and rapid eye movement (REM) sleep. The NHLBI notes that this cycle starts over every 80 to 100 minutes, so a night holds several of them. Exact timing differs from person to person.
Exact timing differs from person to person.
Why sleep cycles matter for waking up
Where you are in the cycle when the alarm rings can change how you feel. A wake-up from deep sleep is often described as bringing heavier sleep inertia. That is the thinking behind apps that try to find a lighter moment. It is also why a short snooze rarely feels like real sleep: a few minutes is nowhere near a full cycle.
Some sleep trackers and bedtime calculators are built on this cycle length.
Be careful with simple rules. The best bedtime is the one that gives you enough total sleep, and cycle maths is only a rough guide.
How AlarmiFex relates
AlarmiFex does not track sleep or detect sleep stages, so it will not choose a light-sleep moment for you. It focuses on the sound and on reliable ringing. If you want tracking, read our AlarmiFex vs Sleep Cycle comparison. The two can sit side by side on one phone.
What AlarmiFex can do is soften the landing. Try a calm alarm sound or a Wake-up Series that builds across your wake-up window. Test your alarm before bed.