Results. In a multivariate model with controls for repeated measures, mean sleep time between consecutive work shifts was short: 6.79 hours between 2 day shifts and 5.68 hours between 2 night shifts (P = .01). Sleep time was much greater between days when no shifts were worked (8.53 hours), consistent with catch-up sleep during these times. Every minute of 1-way commuting time was associated with a reduction of sleep time by 0.84 minutes.