// KNOWLEDGE_BASE
HEALTH & LONGEVITY GLOSSARY
Evidence-based definitions for fitness metrics, biomarkers, and training concepts.
Sleep Science
5 terms
Circadian Rhythm
Well-EstablishedThe roughly 24-hour internal biological clock that regulates sleep-wake cycles, hormone release, and other physiological processes.
Deep Sleep
Well-EstablishedThe most restorative sleep stage characterized by slow brain waves, essential for physical recovery, immune function, and growth hormone release.
REM Sleep
Well-EstablishedA sleep stage characterized by rapid eye movements, vivid dreaming, and muscle paralysis, critical for memory consolidation and emotional processing.
Sleep Efficiency
Well-EstablishedThe percentage of time spent actually sleeping versus total time in bed, a key indicator of sleep quality.
Sleep Latency
Well-EstablishedThe time it takes to transition from full wakefulness to sleep after getting into bed with the intention to sleep.