Keywords chronotype - academic performance - quality of life - university student
Introduction
Sleep is an impressive behavior which is well known as a vital and critical biological
process for body functions, mental health, and quality of life.[1 ] The circadian rhythm is a regular pattern of physiological processes with a duration
of 24 hours.[2 ] A trait linked with circadian rhythms is the so-called chronotype, which pertains
to the priorities related to bedtime, waking, daily activities and other aspects,
and is classified into three types regarding the predominance of the sleep-wake pattern:
morning-, evening-, and neither-type, which does not have a specific dominant rhythm.[3 ] A total of 40% of the adult population is considered to belong to one of the two
extreme groups; on the other hand, 60% are neither-type.[4 ]
Morning-type individuals go to bed early and wake up early, and achieve their peak
mental and physical performance in the first hours of the day.[3 ]
[5 ] In contrast, evening types usually have more irregular sleep and wake schedules,
because they spontaneously tend to be awake at night while waking up at socially-acceptable
times during the week.[6 ] Furthermore, daytime sleepiness is a major problem, reported by 50% of college students
compared with 36% of adolescents and adults. In a study,[7 ] 60% of students reported tiredness or daytime sleepiness or yawning at least 3 days
a week. Thus, evening-type individuals tend to present daytime napping habits, unplanned
oversleeping, excessive daytime sleepiness, and sleep disorders. Studies show that
preference for the evening phase is related to inappropriate psychological functioning,
including depression, anxiety, stress, and difficulty coping, drug use and abuse,
behavioral and emotional problems, and suicide. In summary, evening-type individuals
present academic procrastination, weaker memory, and class absenteeism due to oversleeping
and reduced academic performance.[8 ]
Health-Related Quality of Life (HRQoL) is a multidimensional measure regarding the
physical, emotional, mental, and social components of the well-being and performance
of individuals.[9 ] In an assessment of evening-type students based on the Global Health Scale,[10 ] the subjects scored lower on vitality, physical and mental health, body image, relationships
with their parents and teachers, and school activities.[10 ] On the other hand, in a literature review, morning-type subjects presented a significantly
higher quality of life and less insomnia than evening type individuals, but this depends
to a large extent on individual characteristics such as the overall ability to adapt
to conditions. Evening-type individuals feel more tired, report lower sleep quality,
and complain of more insomnia than those who are morning-type, which may be due to
a discrepancy between social activities and their biological clocks.[9 ]
[11 ]
Due to the diversity in the courses of different academic fields, in the required
assignments, and in the hours specialized classes are held, the chronotype can affect
quality of life and academic performance. Therefore, in the present study, three different
academic fields with different priorities in terms of the skills required to perform
tasks were chosen for comparison: medicine (which requires memory and concentration),
technology (which requires precision and high analytical skills), and art (which requires
long hours of work and high levels of creativity, as well as accompanying other students).
The students were supposed to answer questionnaires on their first and second academic
semesters, and we had decided to ask the questions face-to-face; however, due to the
coronavirus disease 2019 (Covid-19) pandemic in 2020 and the nonattendance that was
forced upon students in universities, there was no other choice than to complete the
questionnaires about the past face-to-face through online classes.
Based on our general observations and different studies, although contradictory, we
expected that there would be a significant relationship between academic performance
and chronotype. We also considered whether the field of study would also have an impact,
so we compared three different fields of study that had not been examined in any other
study. An investigation of the chronotypes of students and the relationship/association
with academic performance and quality of life, with the implementation of appropriate
interventions, could help to reduce the complications caused by poor sleep quality
and daytime low-quality activities.
Materials and Methods
The present descriptive, analytical, cross-sectional study was conducted with 400
medicine, technology and art students enrolled at universities in Tehran between 2018
and 2019, with convenience sampling from January 2020 to January 2021.
To calculate the sample size and estimate the difference between the quality of life
and the sleep disorders, we used a method mentioned in a similar, previously published
study.[12 ] At the limit of 20 points, with the assumption of α = 5% and power of 80%, the minimum
sample size of 100 people in each comparison group. According to the study of academic
performance and comparison between three subgroups of students, a minimum number of
400 subjects was determined. The formula to determine the sample size is as follows:
The students in the three fields chosen had classes during the day, which coincided
with the starting time of the routine of the universities. None of them had night
classes, so their class schedules were very similar.
The exclusion criteria were lack of consent to participate in the study and failure
to fill out all of the questionnaires. The sample was composed of 115 medical, 153
technical, and 132 art students. Due to the Covid-19 pandemic, the questionnaires
were filled out online. At first, the objectives of the research were explained to
the students, then, links to the questionnaires were sent to online student groups
with the coordination of the student representative of each field. The questionnaires
were as follows: a demographics questionnaire, the World Health Organization Quality
of Life: Brief Version (WHOQOL-BREF), the Morningness-Eveningness Questionnaire (MEQ),
the Pittsburgh Sleep Quality Index (PSQI), and the Depression, Anxiety, and Stress
Scale-21 items (DASS-21). In each group, volunteers announced their willingness to
participate and filled out the questionnaires.
The study was approved under the ethics code of IR.IUMS.FMD.REC.1399.346. The demographics
questionnaire contained items on personal characteristics of the students, including
age, gender, marital status, number of households, the field of study, place of residence,
and the grade point average (GPA) at the end of the semester, which was used as the
indicator of academic performance. The questionnaires were identified only by code,
to ensure the confidentiality of the information, and the subjects had the right to
withdraw from the study at any stage.
Measures
As aforementioned, the online survey included scales related to chronotypes, quality
of sleep, and quality of life:
The MEQ is used to distinguish between chronotypes, with scores ranging from 16 to
86, which correspond to 5 categories: 70 to 86–definite morning-type; 59 to 69–moderate
morning-type; 42 to 56–intermediate; 31 to 41–moderate evening-type; and 16 to 30–definite
evening-type. In a study conducted in Iran by Rahafar et al.[7 ] with 268 subjects, the Cronbach alpha coefficient for the MEQ was of 0.71. The Persian
version of this questionnaire is considered to present good validity and reliability
to determine the types of circadian rhythm. The Cronbach alpha for the MEQ in the
present study was of 0.826.
The PSQI) differentiates between poor' and ‘good sleepers by evaluating seven areas:
subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency,
sleep disturbances, use of sleep medication, and daytime dysfunction over the previous
month. Scoring is based on a 0 to 3 Likert scale, and a score of 3 reflects the negative
extreme. A total score > 5 is indicative of a poor sleeper, while a score ≤ 5 indicates
a good sleeper.[13 ] The Persian version of this questionnaire has a validity of 86.5 and a reliability
of 89.5.[6 ] The Cronbach alpha for the PSQI in the present study was of 0.75.
The WHOQOL-BREF is a brief version of the 100-item World Health Organization Quality
of Life Assessment (WHOQOL-100). This scale examines the quality of life in four domains:
physical health, psychological health, social relationships, and environmental health,
and it also assesses overall quality of life and general health. The WHOQOL-BREF contains
26 questions: the first one asks about quality of life in general; the second question
is about the general health status; and the following 24 questions assess quality
of life in the four domains previously metioned.[14 ] In 2006, a research[15 ] was conducted with 1,167 people in Tehran to check the validity and reliability
of this questionnaire. The participants were divided into two groups: those with and
those without chronic diseases. The test-retest reliability values for the subscales
were as follows: physical health – 0.77; mental health – 0.77; social relationships
– 0.75; and environmental health – 0.84.[15 ] The Cronbach alpha for the WHOQOL-BREF in the present study was of 0.933.
The Depression, Anxiety, and Stress Scale (DASS) was designed to assess depression
and anxiety and to investigate the failure of earlier scales in differentiating between
the two conditions. The original DASS contains 42 items that evaluate 3 dimensions
of affective states: depression (DASS-D), anxiety (DASS-A), and stress (DASS-S). The
DASS-21–a shorter version of the DASS – was developed by Lovibond and Lovibond[8 ] (1995) with a lower execution time and more common application in clinical samples
to screen for symptoms of different levels of depression, anxiety, and stress. The
DASS-21 assesses the same three dimensions. each containing 7 questions.[16 ] In the Persian language, by studying a nonclinical population, Salari-Moghaddam
et al.[9 ] showed that the scores of the three subscales are not dependent on gender and level
of schooling, but the depression subscale is dependent on marital status. Moreover,
in their study,[9 ] the scores on the depression subscale presented a correlation of 0.7 with the scores
on the Beck Depression Questionnaire, and the scores on the anxiety subscale scores
presented a correlation of 0.6 with the scores on the Four Systems Anxiety Questionnaire.
All three scales significantly differ between the clinical groups (including major
depressive disorder, generalized anxiety disorder and obsessive-compulsive disorder)
and the group without a clinical diagnosis. The Cronbach alpha coefficient was of
0.85 for the depression and the anxiety subscales, of 0.87 for the stress subscale,
and, the total scale, it was of 0.94.[9 ] The Cronbach alpha for the DASS-21 in the present study was of 0.938.
Statistical Analysis
The data were analyzed using the IBM SPSS Statistics for Windows (IBM Corp., Armonk,
NY, United States) software, version 22.0. The quantitative and qualitative variables
were presented as percentages, frequencies, and mean and standard deviation (SD) values
using frequency distribution tables. The comparison of the subgroups in the case of
qualitative nominal variables was performed using the Chi-squared test, and in every
case in which this test was not accurate enough due to the low expected frequency,
the groups were merged. The subgroups were compared in terms of the qualitative-rank
variables and quantitative variables with nonnormal distribution using the Kruskal-Wallis
test, and analysis of variance (ANOVA) was used for the quantitative variables with
normal distribution. Pearson correlation coefficients were used to determine the correlations
regarding chronotypes, academic performance, and quality of life. Finally, multivariate
regression was used to remove confounding variables such as gender, marital status,
age, and place of residence. In all cases, values of p < 0.05 were considered statistically significant.
Results
First of all, it is extremely necessary to explain about the conditions of the questionnaire
completion and study conduct. The present study included sampling to fill out the
questionnaire that was performed in the first academic semester when the classes were
online due to the coronavirus. While the questionnaires were filled out regarding
the first and second semesters when the classes were held in-person and under routine
conditions of the universities. Therefore, the only change caused by the pandemic
in the present study was that, instead of being filled out face to face, they were
filled out online. Since this information provided was on routine class times, we
believe that the students’ chronotypes were not affected by the pandemic.
The sample was composed of 400 subjects: 115 medical students, 153 technical students,
and 132 arts students. In total, 67.3% of them were women, and 33.7% were men, with
a mean age of 21.06 ± 2.063 years. Data pertaining to the demographics questionnaire
are presented in [Table 1 ].
Table 1
Demographic characteristics of the students according to the field of study.
Group
Variable
Medicine
Technology
Art
All fields
Chi-squared test
Frequency
Percentage
Frequency
Percentage
Frequency
Percentage
Frequency
Percentage
p-value *
Gender
Male
33
28.7
53
34.6
45
34.1
131
32.8
0.545
Female
82
71.3
100
65.4
87
65.9
269
67.3
Marital status
Married
22
19.1
40
26.1
43
32.6
105
26.3
0.062
Single
91
79.1
113
73.9
87
65.9
291
72.8
Widowed/
divorced
2
1.7
−
−
2
1.5
4
1.0
Place of residence
House owned by parents/close relatives
101
87.8
145
94.8
110
83.3
356
89.0
0.008
Dormitory
6
5.2
3
2.00
3
2.3
12
3.00
Shared house with friends
2
1.7
1
0.7
7
5.3
10
2.5
Others
6
5.2
4
2.6
12
9.1
22
5.5
Note: *Values of p < 0.05 were considered statistically significant.
Regarding the findings of MEQ between the GPA (as an academic performance criterion)
and the percentage of people in the qualitative spectrum of morningness-eveningness
(chronotype), there were no statistically significant differences among the students
of the three fields. Moreover, no significant correlation was observed regarding academic
performance and the average MEQ scores. In summary, the chronotype of the participants
was not associated with changes in academic performance (p = 0.606; r = 0.026).
Furthermore, there was a significant correlation between chronotype and quality of
sleep. As exhibited in [Figure 1 ], with the increase in MEQ scores, the PSQI score (the lower the score, the better
the quality of sleep) decreased significantly; thus, we can be concluded that the
morning-type was associated with better quality of sleep (p < 0.001; r= 0.175).
Fig. 1 Correlation between chronotype (MEQ scores) and quality of sleep (PSQI scores) (r = 0.175;
p < 0.001). Abbreviations: MEQ, Morningness-Eveningness Questionnaire; PSQI, Pittsburgh
Sleep Quality Index.
The mean scores on the depression, anxiety, and stress subscales of the DASS-21 were
of 14.6 ± 11.9 (median = 12), 10.1 ± 8.9 (median = 8), and 5.5 ± 10.6 (median = 18)
respectively. These three dimensions presented a negative significant correlation
with the MEQ scores and a positive significant correlation with the PSQI scores ([Table 2 ]); the highest number of correlations observed were between chronotype and stress
and between sleep quality and anxiety ([Table 2 ]). The the most negative correlation observed was between chronotype and stress after
the removal of confounders such as gender, marital status, age, and place of residence.
The stress levels of the students increased 0.196 times with the change of chronotype
from morning to night.
Table 2
Pearson correlation coefficients regarding the DASS-21 subscales and the MEQ and PSQI
scores.
DASS-21 subscale
MEQ (value of r)
PSQI (value of r)
Depression
-0.190
0.429
Anxiety
-0.133
0.472
Stress
-0.246
0.428
Abbreviations: DASS-21, Depression, Anxiety, and Stress Scale-21 items; MEQ, Morningness-Eveningness
Questionnaire; PSQI, Pittsburgh Sleep Quality Index.
The highest scores on the WHOQOL-BREF (better quality of life) were associated with
environmental health, and the lowest, with physical health. Morning-type and better
sleep quality have been associated with better physical and environmental health.
In the evaluation of the correlations involving all aspects of quality of life and
the MEQ and PSQI scores, sleep quality and chronotype were associated with significant
changes in quality of life (p < 0.001) ([Table 3 ]).
Table 3
Pearson correlation coefficients regarding quality of life based on the WHOQoL-BREF
and MEQ and PSQI scores.
Aspects
Mean
Standard deviation
Median
Range
Value of r
MEQ score
(p-value *)
PSQI score
(p-value )
Physical health
45.3
12.8
46.1
0–78.6
0.113 (0.024)
-0.423 (< 0.001)
Psychological health
53.1
13.7
54.2
16.7–83.3
0.095 (0.058)
-0.449 (< 0.001)
Social relationships
54.3
21.1
58.3
0–100
0.097 (0.053)
-0.322 (< 0.001)
Environmental health
59.8
16.1
59.4
9.4–100
0.130 (0.009)
-0.324 (< 0.001)
Total
82.0
13.4
82
37–114
0.412 (0.005)
-0.461 (< 0.001)
Abbreviations: MEQ, Morningness-Eveningness Questionnaire; PSQI, Pittsburgh Sleep
Quality Index; WHOQOL-BREF, World Health Organization Quality of Life: Brief Version.
Note: *Values of p < 0.001 were considered statistically significant.
Discussion
The present study was conducted to investigate the effect of the chronotype on the
quality of life and academic performance of medicine, technology and art students.
Due to the existence of conflicting information regarding the association of chronotype
and academic performance, we decided to investigate this issue, and we expected that
this relationship would be confirmed based on our general observations and on the
findings of previous studies[17 ]
[18 ]
[19 ] that showed that morning-type students were more associated with higher academic
performance than evening-type students. We also questioned whether the field of study
would have any impact on this issue, so we compared three different fields that had
not been investigated in previous studies. We found no significant association regarding
chronotype and academic performance, but there was a significant association between
chronotype and quality of life: morning-type students were associated with a better
quality of life.
Chronotypes and Field of Study
In the present study, the chronotypes of the sample were not significantly different,
apparently due to the lack of influence of the individual characteristics of the students
on their choice of field of study. In the current education system of Iran, students
must take a comprehensive entrance exam (called Konkour ) at the end of high school, which defines their academic field. Said field of study
would essentially determine their futures in terms of career, income, and even family;
thus, most students do not choose their favorite fields, and other criteria such as
social status, family factors and friends, as well as economic issues take priority
over individual interests.[20 ] Therefore, comparing the chronotype of students of different fields of study in
Iran is limited to domestic studies. However, to the extent of our knowledge, even
in foreign studies, they did not find an authentic document on this matter. Nevertheless,
in 2013, Anbari et al.[21 ] reported that the relationship between satisfaction with the academic field and
mental health is of special importance to improve academic performance and progress,
as well as the learning rate.
Chronotypes, Sleep Quality, and Academic Performance
Sleep disorders, including lack of sleep, affect the daily performance of students.
The feeling of tiredness at the onset and sleepiness throughout the day, as well as
decreased concentration and lack of attention in activities, are among the effects
of sleep disorders and of the chronotype.[10 ] Medeiros et al. have shown that chronotypes affect the sleep-wake cycle, and irregularity
in this cycle and sleep deprivation also affect learning.[22 ]
In a study published in 2018, Akram et al.[23 ] assessed the possible relationship between chronotype and learning approach (deep
learners versus surface learners); the academic performance of morning- and evening-type
individuals did not differ, but deep learners had better academic outcomes than their
counterparts, and morning-type subjects indulged in deep learning, while evening-type
individuals indulged in surface learning. Therefore, it can be said that the interaction
between chronotype and learning approach significantly determined academic achievement.
These findings gave the impression that the chronotype could impact academic performance
not directly, but indirectly, through the learning approach.[23 ] On this matter, the present study has shown the lack of a direct effect of the chronotype
on academic performance.
In 2016 Itzek-Greulich et al.[24 ] reported that morning-type subjects achieved better grades than evening type subjects
in classes taught in the morning, unlike the classes taught in the afternoon. Additionally,
in 2015, van der Vinne et al.[25 ] reported that evening-types had poorer academic performance than morning types on
morning examinations, but not on afternoon examinations. Liaghatdar and Ashoorion[26 ] (2011) discussed how, in the planning of the syllabus in higher education, difficult
and special courses are usually taught in the early morning, and night students suffer
from academic decline in difficult courses that require better cognitive performance.
The authors[26 ] recommended that difficult special courses be offered at times when all student
groups have better cognitive performance.
Lima et al.[11 ] conducted a study in 2002 with the aim of determining the effect of different starting
times of classes on the chronotypes of 27 medical students; in line with the present
study, they used the MEQ and PSQI. Better sleep quality, sleep onset delay, and longer
sleep duration were observed with a late schedule. Meanwhile, despite the changes
in starting times, the chronotype patterns of the sample did not change.[11 ] According to the findings of the aforementioned studies, we can deduce that significant
changes in the academic performance of students will not be witnessed by changing
the starting hours of classes alone.
Seoane et al.[27 ] published a systematic review in 2020 about “sleep disruption in medicine students
and its relationship with impaired academic performance”. The meta-analysis showed
that poor sleep quality and excessive daytime sleepiness were mildly but significantly
associated with impaired academic performance. In the present study, the negative
effect of sleep quality on quality of life supports this finding by Seoane et al.[27 ]
The relationship between chronotype and academic performance has been investigated
in several similar studies, which have reported a weak to moderate correlation.[17 ]
[18 ]
[28 ]
[29 ]
[30 ] In the present study, this correlation was predictably not significant, considering
that most participants (60.5%) presented an intermediate chronotype.
Chronotype and Quality of Life
According to our findings, the quality of life did not differ significantly among
the three subgroups of students. In addition, the investigation of the correlation
involving all aspects of quality of life and the MEQ and PSQI scores revealed that
the chronotype was associated with changes in the quality of sleep and of life. Furthermore,
better sleep quality was associated with better psychological status, and nonmorning
chronotypes were associated with worse psychological status.
Roeser et al.[31 ] (2012) assessed if eveningness is negatively correlated with quality of life among
adolescents. In their study, morning-type adolescents reported significantly better
quality of life and fewer insomnia symptoms compared to evening type adolescents.
In the total sample, insomnia symptoms mediated the relationship between chronotype
and quality of life. In evening-types, the strongest predictor of HRQoL was the degree
of sleep-related cognitive dysfunction; in morning-types, it was general self-efficacy.
In line with Roeser et al.,[31 ] in the present study, nonmorning-types reported significantly lower quality of life
than morning-types in all aspects: physical health, psychological health, social relationships,
and environmental health.
The findings of the study by Wong et al.[32 ] presented the greatest similarity with those of the current study, for they have
reported that , academic performance, physical health, and psychological health could
be predicted based on the duration and quality of sleep. They[32 ] also reported that certain sleep behaviors directly predicted daytime functions,
while other behaviors had an indirect effect on daytime functions through negative
moods, such as anxiety.
Assessing a multi-university sample of college students, Becker et al.[33 ] (2018) reported that anxiety and depression symptoms were uniquely connected to
disruptions in most sleep component domains of the PSQI. However, anxiety (but not
depression) symptoms were uniquely associated with more sleep disturbances and use
of sleep medication, whereas depression (but not anxiety) symptoms were uniquely associated
with increased daytime dysfunction. Depression and anxiety symptoms were each independently
associated with poor sleep status.[33 ]
In this regard, the present study has confirmed the remarkable impact of anxiety on
the quality of sleep and, thus, the quality of life of the students. Therefore, healthy
sleep patterns are essential for better adaptation in university years.
The strengths of the present study included sampling students of three different fields.
The difference in the attitudes of the students in each of the subgroups, the specialized
and nonspecialized courses offered in each of the fields, and even the social relationships,
the socioeconomic status and the family culture, could affect the sleep-wake pattern,
quality of life, and academic performance. Thus, the fact that we assessed students
of different files has made the present study more valuable, especially, since to
the best of our knowledge, almost all of the studies published on this topic only
assessed medical students.
Limitations
The only limitation of the present research was that the questionnaires had to be
filled by the participants themselves, so the scores may be influenced by the different
perceptions of the participants regarding the questions or the choice of options due
to unfamiliarity with Likert scoring. This restriction was an unexpected consequence
of the Covid-19 pandemic, and it can be removed if the questionnaires are completed
face-to-face under normal conditions.
Conclusion
The present study indicated that the chronotype of students has no significant effect
on academic performance, but it has effects on their quality of life. However, the
studies conducted so far have not stated that changing the class starting times is
a definite influencing factor to reduce sleep quality problems, such as lack of sleep,
sleepiness and daytime fatigue, and reduced concentration and vigilance in the performance
of tasks that require a lot of precision and attention. Notwithstanding, society empirically
still emphasizes improving their academic performance in the case of a better quality
of sleep. Therefore, more studies are essential to establish an effective approach
that can improve the academic performance of different chronotypes.
