Fig. 3.

Sleep Duration in the Hospital. Average hours that interns reportedly slept in the hospital during extended duration (greater than 24 hour) on-call shifts as a percentage of 17,003 monthly survey reports collected from 2,737 resident physicians. Average hours of sleep obtained during extended duration shifts reported by interns for each week were averaged over the four weeks of each month to derive the value for each monthly survey report. Figure and legend reprinted with permission from: Barger LK, Cade BE, Ayas N, Cronin JW, Rosner B, Speizer FE, Czeisler CA, N Engl J Med 2005;352:125–134 (²⁴).