Table 1.

Driving Schedules and Characteristics of 80 Long-Haul Truck Drivers.^*

Driving Schedule	Description of Schedule	No. of Drivers	Age	Height	Weight	Body-Mass Index†	Perceived Amount of Sleep Needed‡
			yr	cm	kg		hr
Steady day	10 hours of driving beginning at about the same time each morning (9 a.m.) for 5 trips	20	49±8	179±5	94±13	29.2±3	7.0±1
Advancing night	10 hours of driving beginning at 9:30 a.m. on day 1 and2 to 3 hours earlier on each subsequent day for 5 trips	20	44±11	181±5	99±22	30.0±6	7.0±1
Steady night	13 hours of driving beginning at about the same time each evening (11 p.m.) for 4 trips	20	40±11	180±8	92±16	28.6±6	6.9±1
Delaying evening	13 hours of driving beginning at 11:30 a.m. on day 1 and1 hour later on each subsequent day for 4 trips	20	38±7	179±8	89±14	27.9±4	7.8±1
All schedules		80	43±10	180±5	94±17	28.9±5	7.1±1

^*Plus–minus values are means ±SD.

^†The body-mass index is calculated as the weight in kilograms divided by the square of the height in meters.

^‡Drivers were asked to respond to the following: “My ideal amount of sleep is X hours.”