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

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*Corresponding author: E-mail: a_fakhari@yahoo.com;
British Journal of Medicine & Medical Research
15(8): 1-6, 2016, Article no.BJMMR.24571
ISSN: 2231-0614, NLM ID: 101570965
SCIENCEDOMAIN international
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Sleep Duration the Night before an Exam and Its
Relationship to Students’ Exam Scores
Ali Fakhari
1*
, Niloufar Sadr Kheradmand
2
and Neda Dolatkhah
3
1
Research Center of Psychiatry and Behavioral Sciences, Tabriz University of Medical Sciences,
Tabriz, Iran.
2
Tabriz Azad University of Medical Sciences, Tabriz, Iran.
3
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
Editor(s):
(1) Domenico De Berardis, Department of Mental Health, National Health Service, Psychiatric Service of Diagnosis and
Treatment, “G. Mazzini” Hospital, Italy.
Reviewers:
(1) Anonymous, Department of Psychiatry, Gujarat University, India.
(2)
Jun Kohyama, Tokyo Bay Urayasu Ichikawa Medical Center, Japan.
(3)
Jyotsana Shukla, Amity Institute of Behavioral and Allied Sciences, Amity University, Lucknow, India.
Complete Peer review History:
http://sciencedomain.org/review-history/14506
Received 26
th
January 2016
Accepted 22
nd
April 2016
Published 7
th
May 2016
ABSTRACT
Background:
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
2
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.
1. INTRODUCTION
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.
2. MATERIALS AND METHODS
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
3
history. The exam scores and students’
educational history were accessible by obtaining
students’ exam papers via course scholarship
numbers.
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).
3. RESULTS
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
students
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).

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Table 1. Summary statistics for characteristics of study participants (n=200)
Variables
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
Habitat
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
hours
≤ 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
score#*
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
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4. DISCUSSION
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.
5. CONCLUSION
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.
COMPETING INTERESTS
Authors have declared that no competing
interests exist.
REFERENCES
1. Colten Harvey R, Altevogt Bruce M. Sleep
disorders and sleep deprivation: An unmet

Fakhari et al.; BJMMR, 15(8): 1-6, 2016; Article no.BJMMR.24571
6
public health problem. Washington, DC:
National Academies Press (US),
Committee on Sleep Medicine and
Research; 2006.
2. Welstein L, Dement WC, Redington D,
Guilleminault C, Mitler MM. Insomnia in the
San Francisco by Area: a Telephone
Survey. In: Guilleminault C, Lugaresi E,
editors. Sleep/Wake disorders: Natural
history, epidemiology, and long-term
evaluation. New York: Raven Press.
1983;73-85.
3. Mellinger GD, Balter MB, Uhlenhuth EH.
Insomnia and its treatment. Prevalence
and correlates. Arch Gen Psychiatry.
1985;42:225–232.
4. Partinen M, Guilleminault C. Daytime
sleepiness and vascular morbidity at
seven-year follow-up in obstructive sleep
apnea patients. Chest. 1990;97(1):27–31.
5. Rocha LF, Guerra HL, Lima-Costa MFF.
Prevalence of insomnia and associated
socio-demographic factors in a Brazilian
community: The Bambu study. Sleep Med.
2002;3(2):121–126.
6. Pires MLN, Benedito-Silva AA, Mello MT,
Del Giglio S, Pompeia C, Tufik S. Sleep
habits and complaints of adults in the city
of São Paulo, Brazil, in 1987 and 1995.
Braz J Med Biol Res. 2007;40(11):1505-
1515.
7. Perez-Chada D, Perez-Lloret S, Videla AJ,
Cardinali D, Bergna MA, Fernández-
Acquier M, et al. Sleep disordered
breathing and daytime sleepiness are
associated with poor academic
performance in teenagers. A study using
the Pediatric Daytime Sleepiness Scale
(PDSS). Sleep. 2007;30(12):1698-703.
8. Drake C, Nickel C, Burduvali E, Roth T,
Jefferson C, Badia P. The pediatric
daytime sleepiness scale (PDSS): Sleep
habits and school outcomes in middle-
school children. Sleep. 2003;26(4):455–
458.
9. Nojomi M, Ghalhe Bandi MF, Kaffashi S.
Sleep pattern in medical students and
residents. Arch Iran Med. 2009:12(6):542-
9.
10. Veasey S, Rosen R, Barzansky B, Rosen
I, Owens J. Sleep loss and fatigue in
residency training: A reappraisal. JAMA.
2002;288(9):1116-24.
11. Curcio G, Ferrara M, De Gennaro L. Sleep
loss, learning capacity and academic
performance. Sleep Med Rev. 2006;10(5):
323–337.
12. Wolfson AR, Carskadon MA. Sleep
schedules and daytime functioning in
adolescents. Child Dev. 1998;69(4):875-
87.
13. Ng EP, Ng DK, Chan CH. Sleep duration,
wake/sleep symptoms, and academic
performance in Hong Kong secondary
school children. Sleep Breath. 2009;13(4):
357-67.
14. Linde L, Bergström M. The effect of one
night without sleep on problem-solving and
immediate recall. Psychol Res. 1992;54:
127-136.
15. Falleti MG, Maruff P, Collie A, Darby DG,
McStephen M. Qualitative similarities in
cognitive impairment associated with 24 h
of sustained wakefulness and a blood
alcohol concentration of 0.05%. J Sleep
Res. 2003;12(4):265-74.
16. Kahn A, Van de Merckt C, Rebuffat E,
Kahn A, Van de Merckt C, Rebuffat E, et
al. Sleep problems in healthy
preadolescents. Pediatrics. 1989;84(3):
542-546.
17. Ohayon MM, Smirne S. Prevalence and
consequences of insomnia disorders in the
general population of Italy. Sleep Med.
2002;3(2):115-20.
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