How much deep sleep do you need? There is no single target
Learn why there is no single deep-sleep target, how laboratory reference values differ from wearable estimates, and when a score needs more context first.
Read the guideSleep Lab / 04
Sleep Science
Plain-language explanations of sleep stages, timing and sleep measurement.
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The complete category contains five authored guides.
What is REM sleep? Its place in the sleep cycle
What is REM sleep? See where it sits in the sleep cycle, how it changes through the night, and why personal stage estimates need careful limits in context.
Read the guideStages of sleep: a map of REM and non-REM cycles
Map the stages of sleep, see how REM and non-REM alternate, and learn why a population cycle description is not a personal stage target for one person.
Read the guideSleep Science guides.
Five pages, ordered by the researched hub priority.
How much deep sleep do you need? There is no single target
Learn why there is no single deep-sleep target, how laboratory reference values differ from wearable estimates, and when a score needs more context first.
What is REM sleep? Its place in the sleep cycle
What is REM sleep? See where it sits in the sleep cycle, how it changes through the night, and why personal stage estimates need careful limits in context.
Stages of sleep: a map of REM and non-REM cycles
Map the stages of sleep, see how REM and non-REM alternate, and learn why a population cycle description is not a personal stage target for one person.
What is circadian rhythm? A guide to daily timing
What is circadian rhythm? Learn how roughly 24-hour patterns, light and darkness, the brain, and melatonin relate without self-diagnosing a disorder at home.
The importance of sleep shows up in everyday tasks
Understand the importance of sleep through bounded effects on attention, learning, memory, decisions, reaction time, and errors, without inflated claims.