Is there a relationship between adequate sleep and academic performance?

Written by: Arnav Kaul

The undergraduate experience is a tough transition for most students – constantly facing midterms, assignments and exams presents them with a predictably high level of stress. Many students move to a new city to attend their post-secondary institutions, further creating some measure of tension due to a new environment. Finally, shifting into university means new social circles and niches for students to fill, piling on to the already mounted-high pressures faced by them. Inevitably, to be able to cope with these numerous stressors, some aspect of the students’ lives must take a toll, which in many cases ends up being the time (or quality) of their sleep.


The Study

Numerous studies have been performed regarding sleep and stress levels in students, which altogether paint a holistic image of pressures and coping mechanisms. One such paper, written by Gomes, Tavares and de Azevedo (2011) analyzes students’ academic performance in relation to how many nights they felt they had an adequate amount of sleep. The paper was written in the light of many findings based on the role of sleep in short-term and long-term memory, as well as general cognition. The paper lists two overarching goals in terms of findings – to determine the direct or explicit impact sleep has on grades, and to find any sleep-related long-term predictors pertaining to academic performance.


What was being analyzed?

The study takes a look at 1654 students who attended a major Portuguese University full-time. The participants were between the ages of 17-25, and spread between a variety of programs and years. Several questionnaires were presented to each student, analyzing a wide array of variables including (but not limited to) demographic, past academic performance, current class and study times, sleep quantity, sleep quality, and sleep irregularity. Qualitative factors such as sleep quality were assessed in a scale format from 0 to 4. Academic performance as a result was measured in two variables – a self-assessment and an objective final grade, measured in terms of a standardized z-score to account for bias from different courses.


How were the results obtained?

Ethics approval was obtained as needed, and one professor from each university level was asked to present the surveys to their students as a voluntary and confidential method of data collection at the end of each class. Collection occurred at noon in the middle of the term to account for any bias from holidays and breaks. University records provided final grades for the students that consented to the survey and study process. Data was then analyzed for any significant findings.


How was data analyzed?

Mean values for sleep and academic performance variables were taken. Analysis of variance (ANOVA) was conducted along with z-score conversions to be able to compare a standardized set of variables to amount of time the participants slept sufficiently. Only 1240 of the participants were used in the analysis due to missing or incomplete data on the part of the remaining students. Students were grouped in terms of when they slept at night (i.e. earlier or later) and how many nights they had adequate sleep. In addition, students who were previously failing their programs (11.1%) were in a different group than students who were passing (88.9%) based on previous GPA.


What did the data find?

Among some of the statistically significant findings, it can be seen that students who achieved a higher z-score and therefore higher grades tended to sleep earlier at night on weekdays as well as weekends. In addition, they tended to sleep for a longer period of time and reported better sleep quality. Another interesting result drawn from the data analysis is that more stable bedtimes were also correlated with higher grades. In students that were failing, later and more variable sleep-wake times were noted.


What did the article conclude?

The article raises several interesting points of discussion. Firstly, the authors mention their use of the frequency a student felt they received adequate sleep as a measure of “good” sleep as opposed to the actual number of hours a student slept. This personalizes the amount of sleep to each student and may account for some performance bias. The study does note that while there is a correlation between sufficient sleep and academic performance, the biggest factors in predicting academic performance are previous achievements and class attendance. Finally, a third point of discussion that can be taken from the paper is that sleep-related medications or disorders such as sleep apnea or narcolepsy were not accounted for in the data. These points demonstrate a need for further research on the subject.


Concluding Ideas

It is important to note that while other factors are in play, a statistically significant correlation does exist between stable, sufficient sleep and better grades in postsecondary education. In the bigger picture, this finding puts into perspective the choice of sacrificing sleep to study – time management and more efficient organization may be better alternatives to sleeping less in order to do well academically.



Gomes, A. A., Tavares, J., & de Azevedo, M. H. P. (2011). Sleep and academic performance in undergraduates: a multi-measure, multi-predictor approach. Chronobiology International, 28(9), 786-801.

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