Sleep Med Psychophysiol.  2008 Dec;15(2):87-93.

Sleep Patterns and Academic Performance in Medical Students

  • 1Center for Sleep and Chronobiology, Seoul National University Hospital, Seoul, Korea.
  • 2Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, Seoul, Korea.


INTRODUCTION: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only few studies on the sleep patterns of medical students in Korea. Therefore, the present study aimed to investigate the life style and sleep patterns of Korean medical students and the impact they have on the students' academic performance.
A questionnaire package was administered to the 3rd year medical students at the Seoul National University to examine their sleep patterns on weekdays and weekends. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI) and GPA (Grade Point Average) that are considered relevant to their sleep patterns. A total of 110 students (85 males and 25 females, mean age 24.4+/-20.6) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's rank correlation and ANOVA. P-values of less than 0.05 were considered statistically significant in all analyses.
The weekend bedtime was significantly delayed (01:24 on weekday; 03:12 on weekend; t=-5.23, p<0.01), the weekend rise time was delayed (07:36 on weekday; 10:30 on weekend; t=-24.48, p<0.01) and the total sleep time was increased on weekends (5:57 on weekday; 8:17 on weekend; t=15.94, p<0.01). They wished to sleep for 7 hours 6 minutes which was different from their actual weekday total sleep time (t=-11.41, p<0.01). The poor sleeper group had lower GPAs than the good sleeper group (t=2.05, p<0.05). The GPA of medical students were negatively correlated with age (r=-0.23, p<0.05), daily amount of smoking (r=-0.78, p<0.01), total amount of smoking (r=-0.75, p<0.01), weekday sleep latency (r=-0.23, p<0.05), weekend sleep latency (r=-0.23, p<0.05) and PSQI score (r=-0.30, p<0.01).
Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the responded students were experiencing poor sleep quality, and the GPAs of the poor sleeper group were lower than those of the good sleeper group.


Sleep; Medical students; Academic performance
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