ACGME duty‐hour limitations were intended, in part, to reduce resident fatigue and decrease its many negative consequences. Prior data suggest fatigue‐related reductions in patient safety and resident well‐being. We aimed to assess the factors associated with fatigue in interns in cognitive specialties following implementation of duty‐hour limitations. We hypothesized that factors other than duty hours were more strongly associated with intern fatigue.


We distributed an anonymous survey to all interns at the University of California, San Francisco, in the spring of 2004 by campus mail and postal mail and at conferences. Surveys contained validated questions related to fatigue (Chalder Fatigue Scale), sleep (Medical Outcomes Study Sleep Scale), and stress (Cohen Perceived Stress Scale), as well as questions developed by authors through expert opinion, focus groups, and pilot testing regarding the number of hours worked, teamwork, and work life satisfaction. Interns in cognitive specialties (internal medicine, family medicine, pediatrics, and psychiatry) were selected as a group for analysis because they exhibit similar patient care practices and training goals. Univariate statistics characterized the distribution of responses. Pearson correlations elucidated bivariate relationships between fatigue and other variables. Multivariate linear regression models identified factors that were independently associated with fatigue.


One hundred and seventeen interns in cognitive specialties were eligible for the study, 85 of whom responded to the survey (73%). In regression analysis including the factors working more than 80 hours per week, sleep quality, perceived stress, work life satisfaction, and teamwork, only quality of sleep was significantly associated with fatigue (P < .0001). To explore the potential mediating effect of sleep, a secondary model including the same factors was constructed. This analysis revealed that only perceived stress was significantly associated with quality of sleep (P = .02). Working more than 80 hours was not associated with quality of sleep or fatigue.


In this cross‐sectional study of interns across cognitive specialties at an academic health center, we found that working long hours was not associated with stress or fatigue. Rather, we found that quality of sleep was associated with fatigue, and perceived stress was associated with quality of sleep. These results suggest that decreasing the number of duty hours alone may not be effective in reducing intern fatigue. Residency programs may need to make more far‐reaching changes to reduce stress in order to improve interns' quality of sleep and lessen their fatigue.

Author Disclosure:

L. D. Friesen, None; A. R. Vidyarthi, None; R. B. Baron, None; P. P. Katz, None.