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Sleep Duration the Night before an Exam and Its Relationship to Students’ Exam Scores



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British Journal of Medicine & Medical Research
15(8): 1-6, 2016, Article no.BJMMR.24571
ISSN: 2231-0614, NLM ID: 101570965
SCIENCEDOMAIN international
Sleep Duration the Night before an Exam and Its
Relationship to Students’ Exam Scores
Ali Fakhari
, Niloufar Sadr Kheradmand
and Neda Dolatkhah
Research Center of Psychiatry and Behavioral Sciences, Tabriz University of Medical Sciences,
Tabriz, Iran.
Tabriz Azad University of Medical Sciences, Tabriz, Iran.
Tabriz University of Medical Sciences, Tabriz, Iran.
Authors’ contributions
This work was carried out in collaboration between all authors. Author AF designed the study and
wrote the protocol. Author NSK wrote the first draft of the manuscript, managed the literature
searches and analyses of the study. Author ND wrote and edited the final draft of the manuscript. All
authors read and approved the final manuscript.
Article Information
DOI: 10.9734/BJMMR/2016/24571
(1) Domenico De Berardis, Department of Mental Health, National Health Service, Psychiatric Service of Diagnosis and
Treatment, “G. Mazzini” Hospital, Italy.
(1) Anonymous, Department of Psychiatry, Gujarat University, India.
Jun Kohyama, Tokyo Bay Urayasu Ichikawa Medical Center, Japan.
Jyotsana Shukla, Amity Institute of Behavioral and Allied Sciences, Amity University, Lucknow, India.
Complete Peer review History:
Received 26
January 2016
Accepted 22
April 2016
Published 7
May 2016
Sleep is an important criterion for preserving physical and mental health. The amount
and quality of our nightly sleep could affect cognitive functions during the following day’s activities.
Recent reviews suggest the important role of sleep in learning and sustaining memory. For the
current study, we evaluated the relationship between nighttime sleep before an exam and
performance on that exam in a group of students from the Azad University.
Methods: Data were collected from a convenience sample of 200 students who completed a
questionnaire. Students’ records and exam scores were obtained by accessing student codes
written on the exams. All data were analyzed using SPSS 16 software.
Results: Sixty-two percent of the students were male, and 38% were female. A slight majority
(56.5%) of students were studying engineering, 16% were studying the basic sciences, and 27.5%
were studying liberal arts. Mean sleep time the night before the exam was 6.43 hours. The mean
Original Research Article
Fakhari et al.; BJMMR, 15(8): 1-6, 2016; Article no.BJMMR.24571
exam score was 15.46. After dividing the sleep period into three groups, we observed that students
who only slept at night received significantly higher exam score than who napped during the day.
Students who slept 6-10 hours at some point within 24 hours before the exam obtained significantly
higher exam scores than did students who slept less than 6 hours.
Conclusions: The results of this study suggest that adequate nighttime sleep the night before an
exam relates to enhanced performance on that exam. Marital status, gender, and habitat did not
have any association with exam scores.
Keywords: Exam; score; sleep; student; university; duration.
Humans spend about one-third of their lives
asleep, yet most individuals know little about the
effects that sleep has on their daily life. Although
the functions of sleep are yet to be fully
elucidated, it is known to be a universal need of
all higher life forms, including humans. The lack
of sleep may be results in serious physiological
consequences [1]. Nearly one-third of adults
report some forms of sleep difficulties [2,3].
Sleep disorders are associated with an increased
prevalence of various somatic and/or psychiatric
disorders, as well as social problems [4,5].
Unfortunately, sleep deprivation is growing
rapidly among young adults. Two cross-sectional
household surveys during 1987 and 1995 (based
on the "UNIFESP Sleep Questionnaire") were
conducted in order to estimate the prevalence of
sleep deprivation among adults living in the city
of São Paulo, SP, Brazil. Overall, there was a
significant increase in insomnia complaints from
1987 to 1995 in the general population. This
major change in less than a decade should be
considered an important public health issue [6]. A
cross-sectional survey of students from seven
schools in four Argentine cities revealed that
complaints of snoring or witnessed apneas and
daytime sleepiness were independent predictors
of poor academic performance [7]. In a study
using the Pediatric Daytime Sleepiness Scale
(PDSS), which is a validated measure for
sleepiness in children, daytime sleepiness was
related to lower school grades and other
negative school-related outcomes [8].
Sleep disturbance is also an important issue
among medical students and residents, and it is
related to age, gender, living conditions,
exercise, and workload [9]. Another study
evaluated the effects of sleeplessness on
cognition, performance, and health, which
described the effectiveness of countermeasures
for sleepiness, including recent work-hour
restrictions among medical students and
residents. These authors suggested innovative
strategies for minimizing the effects of sleepiness
and fatigue on patient care and resident safety
[10]. Sleep patterns and sleepiness can affect
cognitive and psychomotor performance; such
functions are vital for medical students who are
responsible for patients’ survival.
Given the importance that sleep has on
neurological and physical functioning, the goal of
the present study was to assess whether sleep
duration the night before an exam was related to
exam performance.
We evaluated this relationship in a group of
students at Azad University, Tabriz, during one
year and the study sample consisted of 200
students. The study was conducted from October
2009 to October 2010. Convenience sampling
method was performed.
This study was reviewed and approved by Ethics
committee of Tabriz University of Medical
Sciences. All subjects enrolled in the study
provided written informed consent forms for
participate in the study. All procedures performed
in this study were in accordance with the ethical
standards of the institutional and/or national
research committee and with the 1964 Helsinki
declaration and its later amendments or
comparable ethical standards. Information
provided by the students was strictly confidential.
Inclusion criteria were being enrolled as a
student for a minimum of three terms, having
average scores ≥ 10, and having a record of
completing only one study. Students with
average scores of less than 10, students who
had newly arrived, and students who were
involved in more than one study were excluded
from the study.
The average exam scores from last terms
(minimum of three terms) were used as a
baseline measure of students’ educational
Fakhari et al.; BJMMR, 15(8): 1-6, 2016; Article no.BJMMR.24571
history. The exam scores and students’
educational history were accessible by obtaining
students’ exam papers via course scholarship
2.1 Instrument
We created a self-administered questionnaire
based on an exhaustive literature review and an
expert panel. A physician evaluated the content
validity of the questionnaire. Variables were as
follows: gender, age, marital status, field of
study, place of habitation, sleep duration,
sleeping time, and exam score.
2.2 Statistical Analysis
The data was analyzed using SPSS software
(SPSS Inc. IL, Chicago, USA, version 16.0).
Data were presented by mean SD), and
frequency and percent for quantitative and
qualitative variables respectively. Normal
distribution of the data was assessed and
confirmed by one sample Kolmogorov-Smirnov
test. To compare qualitative results, we used chi-
square statistical tests, and we used independent
t tests for quantitative analysis. To investigate the
relationship between exam scores and
mentioned variables bivariate correlation strategy
was applied. Correlation was significant when
P<0.05 (2-tailed).
The mean age of the students was 24.35(±4.26
SD), and 124 students were male (62%), and 76
were female (38%). Forty-one students were
married (20.5%), and 159 were single (79.5%).
One hundred thirteen students were studying
engineering (56.5%), 32 were studying the basic
sciences (16%), and 55 were studying liberal arts
(27.5%). From 200 participants, 14 were living in
a student dormitory (7%), 33 were living in rental
houses (16.5%), and 153 were living with their
families (76.5%).The mean sleep duration time
during the last 24 hours (before the exam) in the
entire student groups was 6.43 (±2.50 SD) hours,
and their last year scores average mean was
14.57 (±1.75 SD). (Table 1, Fig. 1).
The mean sleep duration time in last 24 hours
among males was 6.51 (±2.59 SD) hours and
6.30 (±2.36 SD) hours for females. According to
the results, there was not any significant
difference in sleep duration based on gender
(P = 0.29). The last year average score means
among male and female students were 14.38
(±1.82 SD) and 14.87 (±1.59 SD), respectively,
and there was not any significant difference
between two genders (P = .38). The last exam
score means among male and female students
were 15.42 (±2.86 SD) and 15.53 (±2.83 SD),
respectively. This difference was not statistically
significant (P =0 .92).
Fig. 1. Distribution of exam scores in 200
Mean sleep time during the last 24 hours was
6.59 (±2.57 SD) hours for married students and
6.39 (±2.49 SD) hours for singles, and this
difference was not statistically significant (P =
0.88).The last year average score means among
married and single students were 14.14 (±1.41
SD) and 14.68 (±1.81 SD), respectively. There
was a statistically significant difference between
two groups in last year average scores
(P<0.05).In general there was not any significant
difference in the last exam scores mean between
married and single students (P = 0.45) (Table 2).
The total sleep time during last 24 hours before
the exam had a positive and significant
correlation with last exam scores (rho=.19,
P<0.05). In addition for better describe the sleep
pattern during the last 24 hours before the exam,
the participants sleep duration time was
classified into three groups of less than 5 hours,
6 to 10 hours, and more than 10 hours. From 200
subjects, 68 (34%) students had slept for less
than 5 hours, 121 (60.5%) for 6 to 10 hours, and
11 (5.5%) for more than 11 hours. This sleep
pattern had a positive and significant correlation
with last exam scores (rho=.26, P<0.05). There
was not any significant correlation between last
exam scores and field of the study and habitat of
students (Table 3).
Fakhari et al.; BJMMR, 15(8): 1-6, 2016; Article no.BJMMR.24571
Table 1. Summary statistics for characteristics of study participants (n=200)
Male (n=124) Female (n=76) Total (n=200)
Frequency Percent Frequency Percent Frequency Percent
Marital status
Married 19 15.3 22 28.9 41 20.5
Single 105 84.7 54 71.1 159 79.5
Field of study
Engineering 87 70.2 26 34.2 113 56.5
Basic sciences 16 12.9 16 21.1 32 16
Liberal arts 21 16.9 34 44.7 55 27.5
Dormitory 3 2.4 11 14.5 14 7
Rental houses 30 24.2 3 3.9 33 16.5
With family 91 73.4 81.6 81.6 153 76.5
Sleeping during last 24
≤ 5 hours 41 33.1 27 35.5 68 34
6-10 hours 77 62.1 44 57.9 121 60.5
≥ 11 hours 6 4.8 5 6.6 11 5.5
Last year average score*
≤ 12 14 11.3 1 1.3 15 7.5
12-15 71 57.3 51 67.1 122 61
16-18 31 25 22 28.9 53 26.5
≥ 19 7 5.6 2 2.6 9 4.5
N/A 1 .8 - - 1 .5
Last exam score*
≤12 17 13.7 11 14.5 28 14
12-15 43 34.7 26 34.2 69 34.5
15-18 46 37.1 27 35.5 73 36.5
≥ 19 18 14.5 11 14.5 29 14.5
N/A - - 1 1.3 1 .5
Mean ± SD Min Max
Age# 24.35 4.26 19 47
Sleep time during last 24
hours (hours)#
6.43 2.50 1 14
Last year average
14.57 1.75 10.15 19.13
Last exam score#* 15.46 2.84 8.5 20
# For these variables, Mean, Std.Deviation and range are reports.
* The baseline score is 20
Table 2. Comparing study variables between groups
Variables Mean ± SD Mean ± SD P- value
Male Female
Sleep time during last 24 hours (hours) 6.51 2.59 6.30 2.36 .29
Last year average score* 14.38 1.82 14.87 1.59 .38
Last exam score* 15.42 2.86 15.53 2.83 .92
Married Single
Sleep time during last 24 hours (hours) 6.59 2.57 6.39 2.49 .88
Last year average score* 14.14 1.41 14.68 1.81 .03
Last exam score* 14.73 2.71 15.65 2.85 .45
* The baseline score is 20
P value based on Independent T-test (P> 0.05 N/S)
Table 3. Correlation between last exam score status and mentioned variables
Variable Correlation (rho) P - value
Sleep classification .256* .000
Sleep time (hours) .186# .008
Field of study .069* .331
Habitat .024* .732
Sleep pattern (Day or Night) .007* .921
*based on Spearman’s rho; #based on Pearson correlation; Correlation is significant at the 0.01 level (2-tailed)
Fakhari et al.; BJMMR, 15(8): 1-6, 2016; Article no.BJMMR.24571
Sleep loss and sleep disorders are among the
most common frequently overlooked and readily
treatable health problems. It is estimated that 50
to 70 million Americans chronically suffer from
sleep disorder and wakefulness, hindering daily
functioning and adversely affecting health and
longevity (NHLB). Sleep has a facilitative role in
learning and memory processes. Conversely,
sleep deprivation and/or fragmentation usually
impairs these functions [11].
According to a study by Wolfson et al. [12] most
of the adolescents do not get enough sleep, and
this sleep loss interferes with daytime
functioning. Ng et al. [13] demonstrated that
excessive sleepiness is on the rise, and
sleepiness during classroom lessons is
associated with poorer grades in mathematics
and English courses. While several studies have
highlighted the relationship between sleep and
learning and memory processes, an in-depth
analysis of the effects of sleep deprivation on
student learning and academic performance
seems necessary [11].
In our study, we evaluated 200 students .The
mean exam score was 15.46, and there were no
statistical differences between males and
females on exam scores, the time of day in which
one slept, and sleep duration.
To assess the effect of one night of
sleeplessness on problem-solving and immediate
recall, Linde et al. [14] performed two
experiments with a repeated-measures design.
According to their results, sleeplessness had a
significant negative effect on performance. In a
similar study, fatigue caused greater impairment
than alcohol on the speed of continuous
attention, memory, learning, and accuracy on a
complex matching task [15]. In our study, there
was no significant relationship between the time
of day in which one slept and exam scores.
There were no significant differences in sleep
duration based on field of study. However, after
classifying exam scores, we observed that
students who had only slept during the nighttime
before the exam obtained higher scores.
Kahn et al. [16] revealed that the following
variables were observed among poor sleepers:
lower parental educational and professional
status, parents who were more likely to be
divorced or separated, and more noise or light in
the rooms where they slept. Poor sleepers also
suffered a higher incidence of somnambulism,
somniloquia, and night fears (nightmares and
night terrors) than children who slept well.
Wolfson et al. [12] found that students with
higher scores received about 25 minutes less
sleep and went to bed about 40 minutes later
than those with lower scores. This is somewhat
similar to our findings, where students with
higher exam scores slept an average of 6-10
hours in the 24 hours before the exam. Thus,
adequate, rather than excessive, sleep likely
leads to higher exam results. Our results
demonstrate that sleeping during the night before
an exam (and sleeping at least 6 hours) is
related to better performance. Marital status,
gender, and habitat had not any significant effect
on exam scores, which was similar to results
obtained by Ohayon et al. [17].
To our knowledge, the present study is the only
one that has investigated the relationship
between the sleep pattern during the 24-hour
period before an exam and students
performance. We attempted to minimize bias by
including rigorous exclusionary criteria. However,
as a result, our sample is smaller than most other
studies in this area; thus, additional studies that
include a larger sample might lead to more
accurate and generalizable results.
It is quite obvious that both REM and NREM
sleep are necessary for an efficient learning and
memory performance. A majority of previous
studies revealed that higher course grades and
semester average scores are associated with
longer duration of sleep on nights prior to
examinations. Most studies have investigated the
effect of sleep duration over the course of longer
time periods (i.e., one academic term). However,
the current study has evaluated only the night
before an exam. Additional studies that consider
sleep duration over longer educational terms
(and with multiple exam results) will be
necessary in the future. Only by this way it will be
possible to highlight the real association between
sleep pattern with knowledge and skills, learning
capacity and academic achieves.
Authors have declared that no competing
interests exist.
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© 2016 Fakhari et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License
(, which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Peer-review history:
The peer review history for this paper can be accessed here:
... The pooled mean sleep duration was 7.08 h/d, which is within the range (6.4-7.9 h/d) reported in other countries. [39][40][41][42] The variation between different studies could be partly attributed to the discrepancy in socioeconomic and cultural factors, sampling methods, and measurements. Although the mean sleep duration was within the standard recommended range of 7 to 9 h/d, 34 the proportion of students with less than 6 hours sleep duration was 8.4%, which is higher than the corresponding figure of 5.9% found in a nationwide study in Chinese adults. ...
... The association between sex and sleep pattern has been inconsistent across studies (eg, male students reported longer sleep than females in Korea, but no significant sex difference was found in Iran and Taiwan). 41,42,49 However, no sex difference in sleep pattern and sleep duration was found in this study. ...
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... This can be bidirectional effect between stress and sleep. Fakhari et al has found that sleep duration correlates positively with examination scores thus helping in high achievement [29]. Breakfast consumption is has lowering effect on test anxiety [30,31]. ...
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Reduced sleep time is commonplace for many interns and residents. Recent studies, however, suggest that sleep loss and fatigue result in significant neurobehavioral impairments in healthy young adults. We reviewed studies addressing the effects of sleep loss on cognition, performance, and health in surgical and nonsurgical residents. We describe the effectiveness of countermeasures for sleepiness, including recent work-hour restrictions. A more complete understanding of the issues of sleep loss during residency training can inform innovative strategies to minimize the effects of sleepiness and fatigue on patient care and resident safety.
Study Objectives To develop a measure of daytime sleepiness suitable for middle-school children and examine the relationship between daytime sleepiness and school-related outcomes. Design Self-report questionnaire. Participants Four hundred fifty, 11- to 15-year-old students, from grades 6, 7, and 8 of a public middle school in Dayton, Ohio. Measurements and Results A pediatric daytime sleepiness questionnaire was developed using factor analysis of questions regarding sleep-related behaviors. Results of the sleepiness questionnaire were then compared across other variables, including daily sleep patterns, school achievement, mood, and extracurricular activities. Results Factor analysis on the 13 questions related to daytime sleepiness yielded 1 primary factor (“pediatric daytime sleepiness”; 32% of variance). Only items with factor loadings above .4 were included in the final sleepiness scale. Internal consistency (Chronbach's alpha) for the final 8-item scale was .80. Separate one-way analyses of variance and trend analyses were performed comparing pediatric daytime sleepiness scores at the 5 different levels of total sleep time and academic achievement. Participants who reported low school achievement, high rates of absenteeism, low school enjoyment, low total sleep time, and frequent illness reported significantly higher levels of daytime sleepiness compared to children with better school-related outcomes. Conclusions The self-report scale developed in the present work is suitable for middle-school-age children and may be useful in future research given its ease of administration and robust psychometric properties. Daytime sleepiness is related to reduced educational achievement and other negative school-related outcomes.
Sleep deprivation is common among teenagers. The aim of this study was to investigate the relationship between sleep duration, wake/sleep symptoms, and academic performance among Hong Kong students. The sleep habit questionnaires were distributed to all Year 11 students at an international school that catered to different ethnic groups in Hong Kong. Analysis of various parameters of academic performance and sleep habits and their relationships were undertaken. Fifty-nine students were recruited. The average sleep duration in this group was 7.23 h. The overall prevalence of excessive daytime sleepiness (defined as an Epworth Sleepiness Scale score of >10) was 25.4%. Eleven subjects had excessive class sleepiness, defined as high likelihood to fall asleep during at least one school session. Mathematics performance was positively correlated with sleep duration. Excessive sleepiness on rising was identified as a significant risk factor for poor performance in English and Mathematics. Sleepiness during the third and fourth lessons was identified as a significant risk factor for poor performance in Mathematics only. Sleep deprivation was common in the studied cohort and it was associated with a decrease in Mathematics performance. Excessive sleepiness on rising and sleepiness during third and fourth lessons were associated with poorer grades in Mathematics and English. Excessive daytime sleepiness was reported in 25% of students. Bruxism and snoring were associated with excessive daytime sleepiness.
The aim of the study was to investigate the effect of spending one night without sleep on the performance of complex cognitive tasks, such as problem-solving, in comparison with a purely short-term memory task. One type of task investigated was immediate free recall, assumed to reflect the holding capacity of the working memory. The other type of task investigated was represented by syntactical reasoning and problem-solving tasks, assumed to reflect the processing (the mental transformation of input) and monitoring capacity of the working memory. Two experiments with a repeated-measures design were performed. Experiment 1 showed a significant decline in performance as a function of sleep loss on Raven's progressive matrices, a problem-solving task. No other main effect of sleep loss was found. Experiment 2 had a different order between tasks than Experiment 1 and the time without sleep was increased. A number-series induction task was also used in Experiment 2. A significant, negative effect of sleep loss in performance on Raven's progressive matrices was found in Experiment 2. The effects of sleep loss on the other tasks were nonsignificant. It is suggested that Raven's progressive-matrices task reflects the ability to monitor encoding operations (selective attention) and to monitor mental "computations".
Few data currently exist concerning the sleep problems of preadolescents. A parent report questionnaire concerning sleep habits and problems was developed. The questionnaires were completed by the parents of 1000 unscreened elementary school children attending the third, fourth, and fifth grades. The schools were randomly selected from an urban area. Of the 1000 questionnaires, 972 were completed and could be used for statistical analysis. Among the parents, 24% reported sleeping poorly and 12% regularly relied on sedatives to induce sleep. Sleep difficulties lasting more than 6 months were present in 43% of the children. In 14% (132 of 972), sleep latency was longer than 30 minutes, and more than one complete arousal occurred during the night at least two nights per week. The following variables were seen among the poor sleepers: lower parental educational and professional status, parents who were more likely to be divorced or separated, and more noise or light in the rooms were they slept. They also presented a higher incidence of somnambulism, somniloquia, and night fears (nightmares and night terrors) than the children who slept well. Boys who slept poorly were significantly more likely to have insomniac fathers (P less than .010). Regular use of sedatives was described in 4% (5 of 132) of the children who slept poorly. Among the "poor sleepers," 21% (33 of 132) had failed 1 or more years at school. School achievement difficulties were encountered significantly more often among the poor sleepers than among the children without sleep problems (P = .001). Of the families with children suffering from sleep problems, 28% expressed a desire for counseling.(ABSTRACT TRUNCATED AT 250 WORDS)
Data for this report come from a nationally representative probability sample survey of noninstitutionalized adults, aged 18 to 79 years. The survey, conducted in 1979, found that insomnia afflicts 35% of all adults during the course of a year; about half of these persons experience the problem as serious. Those with serious insomnia tend to be women and older, and they are more likely than others to display high levels of psychic distress and somatic anxiety, symptoms resembling major depression, and multiple health problems. During the year prior to the survey, 2.6% of adults had used a medically prescribed hypnotic. Typically, use occurred on brief occasions, one or two days at a time, or for short durations of regular use lasting less than two weeks. The survey also found a small group of hypnotic users (11% of all users; 0.3% of all adults) who reported using the medication regularly for a year or longer. If we include anxiolytics and antidepressants, 4.3% of adults had used a medically prescribed psychotherapeutic drug that was prescribed for sleep; 3.1% had used an over-the-counter sleeping pill. The majority of serious insomniacs (85%) were untreated by either prescribed or over-the-counter medications.
Sleep and waking behaviors change significantly during the adolescent years. The objective of this study was to describe the relation between adolescents' sleep/wake habits, characteristics of students (age, sex, school), and daytime functioning (mood, school performance, and behavior). A Sleep Habits Survey was administered in homeroom classes to 3,120 high school students at 4 public high schools from 3 Rhode Island school districts. Self-reported total sleep times (school and weekend nights) decreased by 40-50 min across ages 13-19, ps < .001. The sleep loss was due to increasingly later bedtimes, whereas rise times were more consistent across ages. Students who described themselves as struggling or failing school (C's, D's/F's) reported that on school nights they obtain about 25 min less sleep and go to bed an average of 40 min later than A and B students, ps < .001. In addition, students with worse grades reported greater weekend delays of sleep schedule than did those with better grades. Furthermore, this study examined a priori defined adequate sleep habit groups versus less than adequate sleep habit groups on their daytime functioning. Students in the short school-night total sleep group (< 6 hr 45 min) and/or large weekend bedtime delay group (> 120 min) reported increased daytime sleepiness, depressive mood, and sleep/wake behavior problems, ps < .05, versus those sleeping longer than 8 hr 15 min with less than 60 min weekend delay. Altogether, most of the adolescents surveyed do not get enough sleep, and their sleep loss interferes with daytime functioning.