Sleep signals
Numbers need context.
Your tracker can notice a pattern. It cannot know the late meal, the hard conversation, the new medication, or how you felt. These guides show what common signals can tell you—and where certainty ends.
Recovery
Heart rate variability (HRV)
How to read your own trend without turning one recovery score into a diagnosis.
Read the guideSleep architecture
Sleep stages
What wearables estimate, what changes across the night, and where certainty ends.
Read the guideSleep duration
Sleep debt
A useful description of accumulated short sleep—not a precise bill your body pays by the hour.
Read the guideA useful boundary
Consumer sleep data is best at trends, not verdicts.
Rest Coach can use summaries to ask a sharper question and compare repeated patterns. It should not turn an estimated stage, proprietary score, or one unusual night into a diagnosis.