Table 1.

Features constructed for epoch n.

Type	Feature	Collection method
Static	Age, sex, Pittsburgh sleep quality index (PSQI)	PSQI Questionnaire
	Total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), wake ratio, light sleep ratio, deep sleep ratio, REM sleep ratio	Fitbit
Dynamic	ID of epoch n, Fitbit labeled sleep stage for epoch (n − 3) − (n + 3), average heart rate in epoch n, heart rate change in epoch n vs. epoch (n − 1), heart rate change in epoch n + 1 vs. epoch n	Fitbit