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Impact of sleep quality and general health on academic performance.


Sleep quality is defined as "the degree to which restful sleep is maintained during the night, where a healthy normal individual feels refreshed upon waking up and throughout the day." Restful sleep is graded based on the following parameters: Latency until sleep onset, wakefulness after sleep onset, and/or the duration of sleep. [1] Sleep has many important effects on the human body. One of its most important effects is on one's memory, where it plays a role in stabilizing perceived information and facilitating generalized knowledge. [2] Sleep deprivation is a very common behavior observed, especially in students during their academic life. The severity of sleep deprivation differs among students, but the psychological link and behavioral changes seen in patients are very much alarming. [3] A recent study which was done in 2012 in Saudi Arabia indicated that late night sleeping and a decrease in total nocturnal sleep time during the weekdays or weekends and sleepiness during the day are negatively associated with poor academic performance in medical students. [4] Another study shows that 21% of poor sleepers failed 1 or more years at school while similar problems were observed in just 11% of normal sleepers. [5] General health problems affect the sleep quality with stress being the most common one. As a medical student when experiencing such stress, this will eventually cause poor sleep quality, it also will have a significant influence on one's cognitive performance. [5] Thus, affecting the academic performance, which is seen mostly in the students' attention span, memory consolidation, and encoding. Physical and psychological health is also compromised with poor sleep quality and the percentage of disorders increases with the severity of the condition. All students experience stress, but the tremendous amount of knowledge a medical student is required to obtain in a short time period induces stress leading eventually to poor sleep quality and late nocturnal sleep associated with daytime sleepiness. [6] To assess the quality of sleep, the Pittsburgh Sleep Quality Index (PSQI) is commonly used where it is considered the standard questionnaire used in measuring sleep quality and disturbance. In PSQI, the questions address sleep quality regarding duration and fragmentation in addition to susceptibility to health problems retrospectively over a 1-month period using self-reports. The PSQI scores were moderately to highly correlated with measures of sleep quality and sleep problems, and poorly correlated with unrelated constructs. Individuals with sleep problems, poor sleep quality, and sleep restlessness had significantly higher PSQI scores in comparison to individuals without such problems. [7] Bahammam et al. [4] conducted a previous similar research in Saudi Arabia on 2012, but our research describes a different population and sample size as well as studying the relation between sleep quality in addition to general health and the actual graded performance of medical, health sciences students using students' grade-point average (GPA), and the subjective stress they undergo before an exam and after. Demographics, daytime tiredness, class attendance, sleep habits, sleep duration, and fragmentation are included in the study.

Due to the significant applicability of knowledge and continuous information recall, we attempted to correlate the quality of sleep and its effects on general mental health and academic performance of health sciences students. For this reason and many others including how common and popular this is seen among different age groups, this entity is considered a good domain for research.


A cross-sectional study was carried out in a Saudi university in Riyadh, for 12 months starting September 2014. Through convenience sampling technique, 378 students of both genders were randomly chosen (Table 1). Validated self-report questionnaires: PSQI [7] and General Health Questionnaire (GHQ), [8] demographic, and academic information were used.

PSQI is used to measure sleep quality and disturbance. It addresses sleep duration and fragmentation, in addition to susceptibility to health problems retrospectively over a 1-month period. [9] GHQ is used to assess psychological and occupational well-being.

English version of both questionnaires was validated in previous studies and was used in our study.

We used frequency (%) for categorical variables and mean (standard deviation) for continuous variables. Total score for GHQ and PSQI scales were calculated and divided into categories based on quartiles. Pearson correlation coefficient was used to examine correlation. Multiple linear regression model was applied to predict student GPA from sleep quality score and health quality. Multiple linear regression model was also used to predict sleep quality from health quality score and students' GPA.

We defined results to be statistically significant if P < 0.05.


Sleep quality and GHQ scores did not appear to predict academic performance as there was no significant correlation between student sleep quality and general mental health scores and GPA ([r.sup.2] = 0.091, P = 0.477).

When the model was reversed, general mental health (GHQ) scores were found to significantly affect quality of sleep (odds ratio = 0.301, P < 0.001) while academic performance in terms of GPA was not found to significantly affect sleep quality (P = 0.734). Difficulty in initiating sleep and requiring more than 30 min to fall asleep (i.e., sleep latency) as well as waking up throughout the night or very early in the morning were found to be the most common factors that affected sleep quality among the students.


This study shows that significant proportion of students sampled experience sleep deprivation on a regular basis during their studies and do not acquire enough nocturnal hours of sleep per night (Table 1).

We have also shown that reduced sleep quality did not affect student performance in terms of GPA, however that does not rule out the role sleep plays in learning and processing of information. Since we had only measured academic performance in terms of GPA, sleep may play an important role in how student's preform in settings where maximum in information must be retained. We therefore conclude that the effect of sleep quality and general mental well-being on academic achievement is inconclusive since achieving educational goals may be quantified with more indices than formative testing on which GPA is mainly dependent as shown in Tables 2-5.

Our results have also confirmed that a higher level of distress (and thus a higher risk for developing mental illness) as reported by the GHQ scores plays a role in reducing the quality of sleep. This is expected since studies report that a high level of stress frequently causes inability to fall or stay asleep (Table 6).


We concluded that the effect of sleep quality and general mental well-being on academic achievement is inconclusive.


[1.] Roehrs T, Roth T. The Effects of Medications on Sleep Quality and Sleep Architecture; 2012. Available from: http://www. [Last cited on 2013 Oct 04].

[2.] Ahrberg K, Dresler M, Niedermaier S, Steiger A, Genzel L. The interaction between sleep quality and academic performance. J Psychiatr Res. 2012;46(12):1618-22.

[3.] Diekelmann S, Born J. The memory function of sleep. Nat Rev Neurosci. 2010;11(2):114-26.

[4.] Bahammam AS, Alaseem AM, Alzakri AA, Almeneessier AS, Sharif MM. The relationship between sleep and wake habits and academic performance in medical students: A cross-sectional study. BMC Med Educ. 2012;12:61.

[5.] Curcio G, Ferrara M, De Gennaro L. Sleep loss, learning capacity and academic performance. Sleep Med Rev. 2006;10(5):323-37.

[6.] Van Der Werf YD, Altena E, Schoonheim MM, Sanz-Arigita EJ, Vis JC, De Rijke W, et al. Sleep benefits subsequent hippocampal functioning. Nat Neurosci. 2009;12(2):122-3.

[7.] Buysse DJ. Pittsburgh Sleep Quality Index. Pittsburgh: University of Pittsburgh; 1988.

[8.] Goldberg D, Williams P. Criteria description of General Health Questionnaire (GHQ-12); 1988. Available from: http://www. [Last cited 2014 Feb 01].

[9.] Carpenter JS, Andrykowski MA. Psychometric evaluation of the Pittsburgh sleep quality index. J Psychosom Res. 1998;45(1):5-13.

Omar I Modayfer (1), Meshail A Al Aamer (2), Abdulellah M Al Adel (2), Laura I Al Olayan (2)

(1) Department of Medicine, Mental Health Division, King Abdulaziz Medical City, Riyadh, Saudi Arabia, (2) Medical Interns, College of Medicine, King Saud Bin Abdulaziz University for Health Science, Riyadh, Saudi Arabia

Correspondence to: Meshail A Al Aamer, E-mail:

Received: December 03, 2016; Accepted: December 19, 2016

DOI: 10.5455/ijmsph.2017.1266619122016
Table 1: Distribution of students sleeping hours (by range)
across academic year

Sleep hours   6th year   5th year   4th year   3rd year

12-2 am          73         43         28         14
3-5 am           22         6          5          6
6-8 am           1          1          1          4
9-11 am          2          0          3          3
12-2 pm          1          0          1          1
3-5 pm           0          0          0          0
6-8 pm           0          0          3          1
9-11 pm          18         9          25         10
Missing          2          3          0          1
Grand total     119         62         66         40

Sleep hours   2nd year   Dentistry   Grand Total

12-2 am          26         12           196
3-5 am           6           4           49
6-8 am           6           5           18
9-11 am          3           5           16
12-2 pm          2           0            5
3-5 pm           0           0            0
6-8 pm           0           3            7
9-11 pm          11          2           75
Missing          5           1           12
Grand total      59         32           378

Table 2: Correlation between student GPA, sleep quality
score, and health quality (prediction power)

                  GPA    Sleep quality   Health quality

GPA                1
Sleep quality    0.033         1
Health quality   0.055     0.302 **            1

GPA: Grade-point average

Table 3: Regression model summary

Model       R       [R.sup.2]   Adjusted    Standard error
                                [R.sup.2]   of the estimate

1       0.302 (a)     0.091       0.087         2.83742

Table 4: Regression model: ANOVA table

Model           Sum of    df     Mean       F      Significant
               squares          square

  Regression   346.265     2    173.132   21.505    0.000 (b)
  Residual     3445.814   428    8.051
  Total        3792.079   430

Table 5: Regression model result

             Unstandardized     Standardized
             coefficients       coefficients

Model          B      error     Beta      t     Significant

(Constant)   7.210    1.864             3.867      0.000
Health       0.135    0.021     0.301   6.520      0.000
GPA          0.152    0.447     0.016   0.340      0.734

GPA: Grade-point average

Table 6: Descriptive statistics of the student sleep quality
scale items

                                      Count (%)

                                      Less than once   Not during the
Sleep quality item                        a week         past month

Cannot get to sleep within 30 min      105 (24.40)      147 (34.20)
Wake up in the middle of the night     102 (23.70)      174 (40.50)
or early morning
Have to get up to use the bathroom      96 (22.30)      224 (52.10)
Cannot breath comfortably               48 (11.20)      349 (81.40)
Cough or snore loudly                   34 (7.90)       369 (85.80)
Feel too cold                           95 (22.10)      235 (54.80)
Feel too hot                           115 (26.90)      229 (53.50)
Had bad dreams                         153 (35.70)      203 (47.30)
Have pain                               77 (17.90)      314 (73.20)

                                      Count (%)

                                      Once or twice   Three or more
Sleep quality item                       a week       times a week

Cannot get to sleep within 30 min      92 (21.40)      86 (20.00)
Wake up in the middle of the night     85 (19.80)      69 (16.00)
or early morning
Have to get up to use the bathroom     58 (13.50)      52 (12.10)
Cannot breath comfortably               17 (4.00)       15 (3.50)
Cough or snore loudly                   11 (2.60)       16 (3.70)
Feel too cold                          71 (16.60)       28 (6.50)
Feel too hot                            63(14.70)       21 (4.90)
Had bad dreams                         55 (12.80)       18 (4.20)
Have pain                               25 (5.80)       13 (3.00)

Sleep quality item                      Mean [+ or -] SD     Rank

Cannot get to sleep within 30 min      1.37 [+ or -] 1.06     1
Wake up in the middle of the night      1.281 [+ or -] 1      2
or early morning
Have to get up to use the bathroom    1.153 [+ or -] 0.906    3
Cannot breath comfortably             0.998 [+ or -] 0.54     6
Cough or snore loudly                 1.021 [+ or -] 0.504    5
Feel too cold                         1.075 [+ or -] 0.802    4
Feel too hot                          0.977 [+ or -] 0.783    7
Had bad dreams                        0.855 [+ or -] 0.796    9
Have pain                             0.939 [+ or -] 0.597    8
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Article Details
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Title Annotation:Research Article
Author:Modayfer, Omar I.; Aamer, Meshail A. Al; Adel, Abdulellah M. Al; Olayan, Laura I. Al
Publication:International Journal of Medical Science and Public Health
Article Type:Report
Date:Apr 1, 2017
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