Figure 1.

Sample protocols for a subject who typically slept from 23:00 to 07:00. Participants were randomized to Protocol A or Protocol B. Protocol A consisted of a home phase assessment, a laboratory phase assessment, a 5-day break, a laboratory phase assessment, and a home phase assessment. Protocol B consisted of a laboratory phase assessment, a home phase assessment, a 5-day break, a home phase assessment and a laboratory phase assessment. The gray rectangles represent the time required for dim light. The dot represents the time of the first saliva sample, with saliva sampling continuing every 30 min up until 2 h after average bedtime. The black rectangles represent scheduled sleep times. Square brackets indicate approximate arrival and departure times from the laboratory.