Prior studies have placed emphasis on the need for adequate total sleep time for student performance. We sought to investigate the relative importance of total sleep time compared to the timing of sleep and wakefulness for academic performance.
We performed a questionnaire-based survey of college students in October 2007. The questionnaire gathered detailed information on sleep habits including naps, reasons for missing sleep, academic performance, study habits, time spent working outside of school, and stimulant use.
Compared to those with the lowest academic performance, students with the highest performance had significantly earlier bedtimes (p = 0.05) and wake times (p = 0.008). Napping tended to be more common among high performers (p = 0.07). Of importance, there were no significant differences in total sleep time with or without naps, weekend sleep habits, study time, gender, race, reasons for staying up at night, nor in use of caffeinated beverages, over-the-counter stimulant pills, or use of prescription stimulants.
Timing of sleep and wakefulness correlated more closely with academic performance than total sleep time and other relevant factors. These findings have important implications for programs intended to improve academic performance by targeting sleep habits of students.