Difference between good and average student is twenty minutes sleep

If mediocre students were to sleep 20 minutes and 24 seconds longer on weekdays, they might improve their grades. This is suggested in a study that sleep researchers at King Saud University in Saudi Arabia published in BMC Medical Education.

If your grades are nothing to write home about you can of course always try upping them by taking ADHD drugs. You wouldn’t be the only one. But perhaps it’s first worth reading the article by Ahmed BaHammam, who looked at the relationship between study grades and sleep patterns in medical students.

BaHammam divided a group of 410 students into groups on the basis of their grades: average students [115 of them] and excellent students [295].

When he then looked for lifestyle factors that were partially responsible for good or less good grades, he discovered that sleep played a key role. The students with good grades went to bed during the week on average at a quarter to midnight; the students with average grades went to bed at ten past midnight.

The figure below shows the number of hours sleep that the students got during the week. The good students got 6 hours and 17 minutes, whereas the mediocre students only managed 5 hours and 56 minutes.



At weekends both good and mediocre students slept the same amount.

Fifty percent of the students with good grades also said that they thought they got enough sleep. Among the mediocre students the figure was thirty percent.

Not surprisingly, students with good grades felt less sleepy during classes.


The researchers admit that their study doesn’t provide hard evidence that students will get better results if they sleep more. Epidemiological studies can detect relationships, not causalities.

“Because the study was cross-sectional, no conclusions about the long-term effects of insufficient sleep can be drawn”, the researchers write. “Although it is sensible to assume that improving the quality and pattern of sleep will contribute to the improvement of academic performance, a cause-effect relationship has not been established.”

The relationship between sleep and wake habits and academic performance in medical students: a cross-sectional study.



The relationship between the sleep/wake habits and the academic performance of medical students is insufficiently addressed in the literature. This study aimed to assess the relationship between sleep habits and sleep duration with academic performance in medical students.


This study was conducted between December 2009 and January 2010 at the College of Medicine, King Saud University, and included a systematic random sample of healthy medical students in the first (L1), second (L2) and third (L3) academic levels. A self-administered questionnaire was distributed to assess demographics, sleep/wake schedule, sleep habits, and sleep duration. Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). School performance was stratified as “excellent” (GPA ? 3.75/5) or “average” (GPA <3.75/5).


The final analysis included 410 students (males: 67%). One hundred fifteen students (28%) had “excellent” performance, and 295 students (72%) had “average” performance. The “average” group had a higher ESS score and a higher percentage of students who felt sleepy during class. In contrast, the “excellent” group had an earlier bedtime and increased TST during weekdays. Subjective feeling of obtaining sufficient sleep and non-smoking were the only independent predictors of “excellent” performance.


Decreased nocturnal sleep time, late bedtimes during weekdays and weekends and increased daytime sleepiness are negatively associated with academic performance in medical students.

PMID: 22853649 [PubMed – indexed for MEDLINE] PMCID: PMC3419622

Source: http://www.ncbi.nlm.nih.gov/pubmed/22853649

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