Table 1.

Detailed description of sleep parameters

Parameter	Definition	Source of data
Bed time	Clock time representing time in bed	Sleep diary, actigraphy
Wake time	Clock time representing time of awakening	Sleep diary, actigraphy
Time in bed (min)	Time from resting in bed to getting up	Actigraphy
Sleep onset latency (min)	Time from resting in bed to sleep onset	Actigraphy
Sleep onset	First minute of a 10-minute period after bed time in which activity counts were zero	Actigraphy
Wake after sleep onset min)	Time spent awake after sleep onset	Actigraphy
Sleep efficiency, %	Proportion of time in bed spent asleep	Actigraphy
Total sleep time (min)	Time from sleep onset to awakening	Actigraphy
Nighttime awakenings	Number of awakening after sleep onset	Actigraphy
Sleep interval (min)	Minutes between bed time and wake time	Actigraphy