Sleep Stages & Cycles
Learn about the four stages of sleep, how they cycle throughout the night, and why each stage is essential for different restorative functions.
Explore Topic →Sleep is one of the most complex and essential biological processes. For roughly one-third of our lives, our bodies enter a state that repairs tissues, consolidates memories, regulates hormones, and restores cognitive function. Understanding the science of sleep empowers you to make informed decisions about your rest.
Explore Sleep Science Topics
Circadian Rhythms
Discover how your internal 24-hour clock regulates sleep, hormone release, body temperature, and why consistency matters so much.
Explore Topic →Thermoregulation & Sleep
Understand how body temperature drops trigger sleep onset and why environmental temperature is crucial for deep, restorative rest.
Explore Topic →Light & Melatonin
Explore how light exposure—especially blue wavelengths—affects melatonin production and circadian timing.
Explore Topic →Caffeine & Adenosine
Learn how caffeine blocks adenosine receptors, why its half-life matters, and the science behind timing your last cup.
Explore Topic →Sleep Architecture
Understand why we briefly wake between sleep cycles and what causes prolonged middle-of-the-night awakenings.
Explore Topic →Sleep By The Numbers
90
Minutes per sleep cycle
4-6
Sleep cycles per night
20%
Of sleep is REM
7-9
Recommended hours for adults