Circadian Rhythm Aligner
Master your biology. Calculate the optimal times for sleep, caffeine intake, and deep work based on your target wake-up time and chronobiology science.
Set your wake time to visualize your optimal day.
Why 90 Minutes Matters
Sleep is not a uniform block of time. It occurs in cycles, typically lasting about 90 minutes, transitioning through light sleep, deep sleep, and REM (Rapid Eye Movement). Waking up in the middle of deep sleep causes "sleep inertia"—that groggy, disoriented feeling. This tool calculates your bedtime by counting backward in 90-minute increments, aiming to wake you up at the end of a cycle when your brain is already near alertness.
Understanding Your Chronotype
Dr. Michael Breus popularized the idea of four chronotypes. Understanding yours helps align your schedule:
- The Bear: Flows with the sun. Most productive in the late morning. Needs 8 hours.
- The Lion: Early riser. Peak productivity is early morning. Often tired by early evening.
- The Wolf: Night owl. Struggles with mornings. Peak creativity happens late at night.
- The Dolphin: Anxious sleeper. Wired and tired. Needs strict routine to combat insomnia.
The Adenosine & Melatonin Dance
Two chemicals rule your energy. Adenosine builds up while you're awake, creating "sleep pressure." Caffeine blocks adenosine receptors, which is why we suggest a cutoff time (usually 8-10 hours before bed). Melatonin is the "vampire hormone"—it only comes out in the dark. Light exposure in the morning halts melatonin production (waking you up), while blue light from screens at night suppresses it, ruining your sleep quality.