Fig. 2

An example of actigraphic recording of a subject subjectively adapted to shift work. The thin black vertical bars denote activity counts per minute. Colored areas with numbers are described in minutes, and percentages denote the time when the subject was in bed attempting to fall asleep. Those numbers are TIB (time in bed when the subject was in bed) and SEI (Sleep Efficiency Index: percentage of time scored as sleep in TIB), respectively. Red underlining below each day’s horizontal axis denote the time scored as sleep. Violet blocks denote the time when the subject removed the actigraph. Yellow blocks denote the time when the subject was at work