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Advanced Research in Health, Education and Social Sciences: Towards a better practice
53
Chapter IV
SLEEP QUALITY AND STRESS: A LITERATURE REVIEW
NATHÁLIA BRANDOLIM BECKER1, SAUL NEVES DE JESUS2 , RUI
MARGUILHO3, JOÃO VISEU4, KARINA ALEXANDRA DEL RIO5, GUALBERTO
BUELA-CASAL6
1 University of Algarve, Portugal, nathalia_brandolim@msn.com
2 University of Algarve, Portugal, snjesus@ualg.pt
3 University of Algarve, Portugal, rui.marguilho@gmail.com
4 University of Algarve, Portugal, joaonrviseu@gmail.com
5 University of Algarve, Portugal, delriokarina@gmail.com
6 University of Granada, Spain, gbuela@ugr.es
Note: This paper is supported by FCT (CIEO – Research Centre for Spatial and Organizational Dynamics,
University of Algarve, Portugal)
Abstract: The present literature review aims to analyze the research published between 2005
and 2015 relative to the relationship between stress and sleep quality, using the Pittsburgh
Sleep Quality Index (PSQI) as an instrument to assess the sleep aspects. This review was
conducted in May 2015 based on the electronic databases Web of Science and EBSCO. We used
the keywords “sleep quality” and “stress” focusing our target on empirical studies. After
reading the collected studies (n=1267), only those who comprised adult samples were selected,
resulting in a total of 15 studies. It was found that stress is associated with several individual
factors, such as age, employment status, type of work, personality, level of education, and
socio-economic status. When considering the use of the PSQI, stress also influenced the quality
of sleep as a whole and in its specific components. Depression was considered important in
stress relative to the sleep quality. Other relevant variables were the sociodemographic
indicators and socioeconomic status. Therefore, it is essential to assess the context of stress and
sleep quality so one can establish new explanations for their relationship and functions. In
conclusion, it is necessary to develop thorough studies that take into consideration the
importance of complementary variables, i.e., psychosocial, sociodemographic, and
socioeconomic status, in the context of the quality of sleep. In this way, it will be possible to
understand the effects of the quality of sleep in different samples.
Key-words: literature review, PSQI, sleep quality, stress.
INTRODUCTION
Sleep is a vital and complex physiological
process inherent in each individual. In the
last years, several studies (e.g., Nunes da
Silva, Martins Costa, Waquim Machado, &
Lopes Xavier, 2012) found that this process
is affected by social, cultural, and
environmental aspects. Nowadays, the
demands that an individual experiences,
especially from social and organizational
contexts, have resulted in high levels of
stress and poor sleep quality (Kurina et al.,
2011). Moreover, organic disorders have
contributed to an increase in the number of
diseases associated with sleep quality
(Carlson, Campbell, Garland, & Grossman,
2007). The risks associated with sleep
disorders may include cardiovascular
problems (Kashani, Eliasson, & Vernalis,
2012), cancer (Carlson et al., 2007), and
metabolic disorders (Luyster, Strollo, Zee, &
Walsh, 2012; Theadom & Cropley, 2008).
Sibiu, Romania, June 2015
54
Some studies have also established sleep as
an important element in psychiatric
conditions (Baglioni, Nanovska et al., 2014a;
Baglioni, Spiegelhalder et al., 2014b). Poor
quality of sleep and insomnia are related to
emotion, previous studies have observed the
effects of loneliness, grief, hostility,
impulsivity, stress, depression, and anxiety
on sleep (Baglioni, Spiegelhalder,
Lombardo, & Riemann, 2010; Cho et al.,
2013; Gallagher, Phillips, & Carroll, 2010;
Okun, Tolge, & Hall, 2014). Emotion and
sleep have shown a close relationship, which
is increasingly recognized as an important
area of research (Kurina et al., 2011). Recent
studies have reported some mechanisms of
sleep (Carter et al., 2012; Siegel, 2011) in an
effort to understand its behavioral
complexity and advancing beyond
pathological descriptions, trying to
understand the processes that lead to a good
quality of sleep (Hawkley, Lavelle,
Berntson, & Cacioppo, 2011; McHugh,
Casey, & Lawlor, 2011; Mellor, Waters,
Olaithe, McGowan, & Bucks, 2014; Miró,
Cano-Lozano, & Buela-Casal, 2005).
The increasing need to assess which factors
strongly influence the quality of sleep has
grown over the years. It was found that
biological traits are not always associated
with the perception of poor quality of sleep
(Hayase, Shimada, & Seki, 2014), creating
the necessity to understand these
associations. One way to assess the
subjective quality of sleep is through the
Pittsburgh Sleep Quality Index (PSQI). This
instrument provides an accurate picture of
seven different aspects of sleep: (a) sleep
duration; (b) sleep disturbance; (c) sleep
latency; (d) daytime dysfunction; (e) sleep
efficiency; (f) subjective sleep quality; and
(g) use of sleep medication (Buysse,
Reynolds, Monk, Berman, & Kupfer, 1989).
Being a self-report measure, it may be more
relevant in the clinical practice than the
objective sleep measures (Buysse, 2005;
McHugh et al., 2011).
Psychological and psychosocial factors have
contributed significantly to the
comprehension of the sleep quality (McHugh
et al., 2011). Studies have underlined the
importance of evaluating the influence of
stress on the processes concerning the proper
functioning of sleep (Cho et al., 2013;
Gamaldo et al., 2014; Kashani et al., 2012;
Ko, Chang, & Chen, 2010; Okun et al.,
2014), given that it is an essential dimension
of health (Buysse, 2014). Knowing the
importance of stress and sleep quality for
health, conducting a review on the empirical
studies addressing this topic is relevant,
particularly since there are no previous
literature reviews or meta-analysis published
about this relationship.
Stress may conduce to negative health
implications, including increasing the
likelihood of cardiovascular disease, directly
affecting the nervous system, as well as
increasing the probability of involvement in
risk behaviors, such as smoking and
excessive alcohol consumption, which will
propitiate a poor quality of sleep (Hawkley,
Masi, Berry, & Cacioppo, 2006; McHugh &
Lawlor, 2013).
Therefore, our aim is to review the studies
on sleep quality using the PSQI, one of the
main self-report instruments on sleep
evaluation, in order to understand how this
construct relates to stress. With the collected
information, we hope to contribute directly
and indirectly to the increase of individuals’
subjective perception of well-being, health,
and quality of life.
METHOD
Procedure
This review was conducted in May 2015 in
the electronic databases Web of Science
(WoS) and EBSCO. The keywords used
were “sleep quality” and “stress”. The
collected studies should have been published
between 2005 and 2015. The research was
divided in four phases (Figure 1): (a) 1267
references were found using the previously
chosen keywords; (b) the relevance of the
studies was based in the following criteria:
(b1) studies published in scientific journals;
(b2) empirical study; (b3) presence of
enough data to analyse “what has been
studied” and “how it was studied”; and (b4)
the use of the Pittsburgh Sleep Quality Index
(PSQI). Thus, after the second phase, the
Advanced Research in Health, Education and Social Sciences: Towards a better practice
55
number of studies registered was 125; (c)
considering the use of two research sources,
some studies were repeated and, therefore,
excluded, resulting in 76 studies; and (d) in
this last phase, only studies that were
composed by adult samples were considered,
which resulted in 15 articles.
After the fourth phase (i.e., phase d), the 15
selected studies were assessed regarding the
following information: (a) authors; (b) year
of publication; (c) type of sample; (d)
instruments used; and (e) obtained results.
The taxonomy of Montero and León was
applied in the classification of these studies.
Figure 1. Phases of the literature review. In each phase are presented the number (n) of studies that
remained in the sample.
RESULTS
The theoretical perspective was confirmed
by a selection of studies with identical
subjects (i.e., adults). The characterization of
the “sleep” variable had the same approach,
although there are some differences
regarding sleep quality. The “stress” variable
was evaluated in different perspectives, for
instance (a) perceived stress; (b) symptoms
of stress; (c) mood states; and (d) biological
traits. These perspectives were not
discriminated, given that they rely on self-
evaluation methods. The methodological
approach was common to all studies (i.e.,
quantitative approach) and pointed to works
where the PSQI was the instrument used to
evaluate sleep quality in adult samples.
Table 1 displays the authors, year of
publication, type of sample, age/status, and
total number of participants. The total
number of participants was 11025, the
majority were females (8797) while 1777
were males. Moreover, in the studies of Cho
et al. (2013) and Cohrs et al. (2012) a higher
percentage of female participants,
respectively 4966 (about 36% of total
participants) and 1340 (about 10% of total
participants), was registered comparatively
to the other evaluated studies. Regarding the
type of sample, three studies were composed
by pregnant women (Hayase et al., 2014; Ko
et al., 2010; Okun et al., 2014).
Table 2 shows the main results of the studies
conducted on sleep quality and stress.
Table 1. Articles Included in the Literature Review and Participant Characterization (N = 15)
Authors/year Type of sample N
Age/Status Total M/F
Carlson et al. (2007) Adults/Women with breast cancer 66 0/66
Sibiu, Romania, June 2015
56
Cho et al. (2013) Adults/Women workers 4966 0/4966
Cohrs et al. (2012) Adults/Smokers 2314 974/1340
Costa, Zummer, and Fitzcharles
(2009)
Adults/Spondyloarthropathy 125 58/67
Eliasson, Kashani, Dela Cruz,
and Vernalis (2012)
Adults/Soldiers 265 236/29
Gallagher et al. (2010) Adults/Parents caring for children with
developmental disabilities
109 26/83
Gamaldo et al. (2014) Adults/Older blacks 606 153/449
Hayasse et al. (2014) Adults/Pregnant women 56 0/56
Kashani et al. (2012) Adults/ Cardiovascular disease
prevention program
350 138/212
Ko et al. (2010) Adults/Pregnant women 600 0/600
McHugh and Lawlor (2013) Older adults/General population 447 -
Mellor et al. (2014) Adults/General population 582 154/428
Okun et al. (2014) Adults/Pregnant women 170 0/170
Rocha and Martino (2010) Adults/Hospital nurses 203 24/179
Theadom and Cropley (2008) Adults/Fibromyalgia 166 14/152
Total 11025 1777/8797
Note. M = Male, F = Female.
Table 2. Main Results of the Studies Conducted on Sleep Quality and Stress (N = 15)
Authors/year Instruments Results
Carlson et al. (2007) SOSI1; CES-D2; STAI3;
POMS4; PSQI5; BM6
Women with breast cancer had significantly
higher levels of disorder on all
psychological indicators, but there were no
differences between the groups on any of
the biological measures.
Cho et al. (2013) PSQI5; KOSS-SF7; CES-D2
The depressive symptoms of female workers
were closely related to their job stress and
sleep quality. In particular, the lack of
rewards and subjective sleep factors had the
greatest impact.
Cohrs et al. (2012) PSQI
5
; FTND
8
; QSU
9
; BDI
10
;
STAI3; AUDIT11; PSS12
Direct aspects related to smoking seem to
have a strong effect on sleep quality.
Costa, Zummer, and
Fitzcharles (2009)
BASDAI
13
; BASFI
14
; PSQI
5
;
CES-D2; PSS12; ACLS-PAQ15
Higher perceived stress was an independent
contributor of poor sleep quality.
Eliasson, Kashani,
Dela Cruz, and
Vernalis (2012)
PSQI5; PSS12; ESS16; FS17;
MDQ18; BQ19; SQSD20
Soldiers with high stress, depression, poor
sleep quality, and sleep apnea are at
increased long-term risk for cardiovascular
complications.
Gallagher et al.
(2010) PSQI5; QRSF21; SDQ22; SFS23
Parental stress is associated with poor sleep
quality in parents of children with
developmental disabilities.
Gamaldo et al.
(2014) PSQI5; CVRFs24; CES-D2
Perceived stressors, including current
financial hardship or hardship experienced
for an extended period throughout the
lifespan, may influence sleep later in life.
Hayasse et al. (2014) PSQI5; PSS12; BM6 Pregnant women with pregnancy-induced
hypertension and gestational diabetes
Advanced Research in Health, Education and Social Sciences: Towards a better practice
57
mellitus experience higher stress levels than
the non-pregnant women and healthy
pregnant women. Further, the results
indicated that sleep quality worsens during
the third trimester compared with the
second.
Kashani et al. (2012) PSS12; PSQI5; ESS16; FS17;
BQ19
High stress was associated with significant
disorders in sleep duration and quality.
Stress levels also correlated with daytime
consequences of disturbed sleep. The stress-
sleep relationship may be an important
mediator in the association between stress
and cardiovascular disease.
Ko et al. (2010) PSQI5; EPDS25; PSS12
The sleep quality of pregnant women was
related to stress and depression, and
comparatively to the non-pregnant women
they tend to have a poor sleep quality.
McHugh and Lawlor
(2013)
JGSL26; PSQI5; PSS12;
NACI27
The impact of emotional loneliness on sleep
quality in older adults is partly because of
the stress experienced as a result of feeling
lonely.
Mellor et al. (2014) PSQI5; DASS-2128; BQ19
Sleep-related risk factors, such as gender,
psychological symptoms, and risk of sleep-
disorder breathing, although related to sleep
quality, did not have an impact on the
relation between age and sleep quality.
Okun et al. (2014) PSQI5; MMA29; SDD30;
PSS12; IDS31
Perceived stress and financial strain
attenuated the socioeconomic status-sleep
association, indicating that psychological
situations preceding pregnancy are also
important to consider.
Rocha and Martino
(2010) PSQI5; BSSm32
There is a significant correlation between
stress and sleep. Nurses working in the
morning shifts showed higher stress levels
and poorer sleep quality.
Theadom and
Cropley (2008)
DBAS-1033; PSS12; PSQI1;
FAS34; SF-3635
Beliefs about sleep and perceived stress play
a significant role in the sleep quality of
patients with fibromyalgia.
Note. 1Symptoms of Stress Inventory (SOSI); 2Centre for Epidemiological Studies – Depression Inventory
(CES-D); 3Spielberger State-Trait Anxiety Inventory (STAI); 4Profile of Mood States (POMS); 5Pittsburgh
Sleep Quality Index (PSQI); 6Biological Measures (BM); 7The Korean Occupational Stress Scale-Short
Form (KOSS-SF); 8The Fagerström Test of Nicotine Dependence (FTND); 9Questionnaire of Smoking
Urges (QSU); 10Beck Depression Inventory (BDI); 11Alcohol Use Disorders Identification Test (AUDIT);
12Perceived Stress Scale (PSS); 13Bath Ankylosing Spondylitis Disease (BASDAI); 14Bath Ankylosing
Spondylitis Functional Index (BASFI); 15Aerobics Center Longitudinal Study Physical Activity
Questionnaire (ACLS-PAQ); 16Epworth Sleepiness Scale (ESS); 17Fatigue Scale (FS); 18Mediterranean
Diet Questionnaire (MDQ); 19Berlin Questionnaire (BQ); 20Single Question to Screen for Depression
(SQSD); 21Questionnaire on Resources and Stress Freidrich Short Form (QRSF); 22Strenghs and
Dificulties Questionnaire (SDQ); 23Support Functions Scale (SFS); 24Cardiovascular Risk Factor
Composite Score (CVRFs); 25Edinburgh Postnatal Depression Scale (EPDS); 26Jong Gierveld Scale of
Lonelines (JGSL); 27Charlson Co-morbidity Index (NACI); 28Depression, Anxiety, and Stress Scale
(DASS-21); 29Mini Mitter Actiwatch-64 (MMA); 30Sleep Diary Data (SDD); 31Inventory for Depressive
Symptoms (IDS); 32Bianchi Stress Scale Modified (BSSm); 33Dysfunctional Beliefs and Attitudes About
Sleep Scale (DBAS-10); 34Fatigue Assessment Scale (FAS); 35Short-Form Medical Outcomes
Questionnaire (SF-36).
Sibiu, Romania, June 2015
58
DISCUSSION
The present study reviewed the papers that
evaluated the relationship between stress and
sleep quality in adults, using the PSQI as a
measure to assess the sleep aspects. All the
studies were based on self-report ratings,
mainly studying the subjective quality of
sleep.
The type of sample existent in the analyzed
studies (i.e., adults) presents a heterogeneity
level that enables us to verify aspects of
sleep quality and stress in diverse contexts.
Variety is important because nowadays the
quality of sleep and stress are capable of
affecting health both in individuals suffering
from any kind of medical condition as in
individuals from the general population. In
this review we covered samples with
particular characteristics: (a) pregnant
women; (b) smokers; (c) workers; (d)
soldiers; (e) older blacks; (f) parents of
children with developmental disabilities; and
(g) nurses.
We selected the PSQI as an assessment tool
for sleep quality because it addresses seven
aspects of sleep and it is widely used in the
research of this topic. The research on sleep
quality has been carried out with self-report
instruments. On one hand, they are limited
regarding objective evidence, however they
are able to show individual perceptions, thus
becoming useful in the clinical setting
(Buysse, 2005). Moreover, research has
shown that objective assessments (i.e.,
biological traits) do not always address the
psychological disorders that can be evaluated
by subjective measures (i.e., self-reports)
(Hawkley, Lavelle, Berntson, & Cacioppo,
2011).
Our review underlined the influence of stress
on the perceived quality of sleep (Cho et al.,
2013; Gallagher et al., 2010; Gamaldo et al.,
2014; Hayase et al., 2014; Kashani et al.,
2012; Ko et al., 2010; McHugh & Lawlor,
2013; Okun et al., 2014; Rocha & Martino,
2010; Theadom & Cropley, 2008), which
emphasizes the importance of considering
the inclusion of this variable in research on
sleep quality. The high levels of stress in
pregnant women (Hayase et al., 2014; Ko et
al., 2010) and individuals with chronic
diseases (Costa et al., 2009; Theadom &
Cropley, 2008) further worsen their sleep
quality. It is necessary to pay special
attention to pregnant women or people
suffering from any medical condition,
especially if chronic, performing periodic
evaluations. The first reason is the fact that
these individuals are more likely to have
compromised the quality of sleep at some
level (Hayase et al., 2014; Ko et al., 2010;
Okun et al., 2014; Sayar, Arikan, & Yontem,
2002; Wilcox et al., 2000). The second
reason is the possibility of establishing
adequate preventive interventions to avoid
the negative effects of poor sleep quality and
stress. In addition, stress variables, such as
depression (Cho et al., 2013; Eliasson et al.,
2012; Gallagher et al., 2010; Ko et al., 2010;
Okun et al., 2014; Rocha & Martino, 2010),
anxiety, fatigue, confusion (Carlson et al.,
2007; Da Costa et al., 2009; Theadom &
Cropley, 2008), loneliness (McHugh &
Lawlor, 2013), age (Mellor et al., 2014), race
(Gamaldo et al., 2014), socioeconomic status
(Lallukka et al., 2012; Okun et al., 2014;
Patel, Grandner, Xie, Branas, & Gooneratne,
2010), and smoking (Cohrs et al., 2012), can
directly or indirectly influence the self-
perceived quality of sleep.
Improving the quality of sleep is an action
that can be, in some cases, carried out by
manipulating these variables without
necessarily administering medication for
specific purposes. In accordance, studies
should indicate actions to reduce stress and
depression in order to improve the sleep
quality (Ko et al., 2010), for example
massage or relaxation (Bastani, Hidarnia,
Kazemnejad, Vafaei, & Kashanian, 2005),
music therapy, meditation or yoga
(Narendran, Nagarathna, Narendran,
Gunasheela, & Nagendra, 2005), and
psychosocial approaches (McHugh et al.,
2011).
Several mechanisms have been proposed to
explain the relationship between stress and
quality of sleep, including physiological
arousal (Freedman & Sattler, 1982; Van
Reeth et al., 2000) and poor coping
Advanced Research in Health, Education and Social Sciences: Towards a better practice
59
mechanisms to adaptively manage stress,
evidenced by findings from Morin,
Rodrigue, and Ivers (2003) in a sample of
healthy adults suffering from primary
insomnia. This leads to the understanding
that stress is an important part of one of
several variables that influence the quality of
sleep, particularly concerning subjective
evaluation. Regarding biological traits, the
variations are not always significant, neither
in the matter of the quality of sleep nor in the
matter of stress (Carlson et al., 2007; Hayase
et al., 2014).
In conclusion, it is necessary to develop
further studies considering the importance of
complementary variables, i.e., psychosocial,
sociodemographic indicators, and
socioeconomic status, in the context of the
quality of sleep. Also, it is necessary to
understand the relationship between the
quality of sleep and stress, enabling, in the
future, a proper understanding of the effects
on sleep quality in different samples.
REFERENCES
Baglioni, C., Nanovska, S., Regen, W.,
Spiegelhalder, K., Feige, B., Nissen, C., …
Riemann, D. (2014a). Sleep and psychiatric
disorders: A meta-analysis of the last 20
years of research. Journal of Sleep Research,
23, 80-80.
Baglioni, C., Spiegelhalder, K., Lombardo,
C., & Riemann, D. (2010). Sleep and
emotions: A focus on insomnia. Sleep
Medicine Reviews, 14(4), 227–38.
doi:10.1016/j.smrv.2009.10.007
Baglioni, C., Spiegelhalder, K., Regen, W.,
Feige, B., Nissen, C., Lombardo, C., …
Riemann, D. (2014b). Insomnia disorder is
associated with increased amygdala
reactivity to insomnia-related stimuli. Sleep,
37(12), 1907–17. doi:10.5665/sleep.4240
Bastani, F., Hidarnia, A., Kazemnejad, A.,
Vafaei, M., & Kashanian, M. (2005). A
randomized controlled trial of the effects of
applied relaxation training on reducing
anxiety and perceived stress in pregnant
women. Journal of Midwifery & Women’s
Health, 50(4), e36-40. doi
10.1016/j.jmwh.2004.11.008/abstract
Buysse, D. J. (2005). Diagnosis and
assessment of sleep and circadian rhythm
disorders. Journal of Psychiatric Practice,
11(2), 102–115. doi:10.1097/00131746-
200503000-00005
Buysse, D. J. (2014). Sleep health: Can we
define it? Does it matter?. Sleep, 37(1), 9–
17. doi:10.5665/sleep.3298
Buysse, D. J., Reynolds, C. F., Monk, T. H.,
Berman, S. R., & Kupfer, D. J. (1989). The
Pittsburgh sleep quality index: A new
instrument for psychiatric practice and
research. Psychiatry Research, 28(2), 193–
213. doi:10.1016/0165-1781(89)90047-4
*Carlson, L. E., Campbell, T. S., Garland, S.
N., & Grossman, P. (2007). Associations
among salivary cortisol, melatonin,
catecholamines, sleep quality and stress in
women with breast cancer and healthy
controls. Journal of Behavioral Medicine,
30(1), 45–58. doi:10.1007/s10865-006-9082-
3
Carter, M. E., Brill, J., Bonnavion, P.,
Huguenard, J. R., Huerta, R., & de Lecea, L.
(2012). Mechanism for hypocretin-mediated
sleep-to-wake transitions. Proceedings of the
National Academy of Sciences of the United
States of America, 109(39), E2635–2644.
doi:10.1073/pnas.1202526109
*Cho, H. S., Kim, Y. W., Park, H. W., Lee,
K. H., Jeong, B. G., Kang, Y. S., & Park, K.
S. (2013). The relationship between
depressive symptoms among female workers
and job stress and sleep quality. Annals of
Occupational and Environmental Medicine,
25(1), 12. doi:10.1186/2052-4374-25-12
*Cohrs, S., Rodenbeck, A., Riemann, D.,
Szagun, B., Jaehne, A., Brinkmeyer, J., …
Winterer, G. (2012). Impaired sleep quality
and sleep duration in smokers: Results from
the German multicenter study on nicotine
dependence. Addiction Biology, 19(3), 486–
496. doi:10.1111/j.1369-1600.2012.00487.x
*Costa, D., Zummer, M., & Fitzcharles, M.
A. (2009). Determinants of sleep problems
in patients with spondyloarthropathy.
Musculoskeletal Care, 7(3), 143–161.
doi:10.1002/msc.155
*Eliasson, A., Kashani, M., Dela Cruz, G., &
Vernalis, M. (2012). Readiness and
associated health behaviors and symptoms in
Sibiu, Romania, June 2015
60
recently deployed army national guard
solders. Military Medicine, 177(11), 1254–
1260. doi:10.7205/MILMED-D-11-00242
Freedman, R. R., & Sattler, H. L. (1982).
Physiological and psychological factors in
sleep-onset insomnia. Journal of Abnormal
Psychology, 91(5), 380–389.
doi:10.1037/0021-843x.91.5.380
*Gallagher, S., Phillips, A. C., & Carroll, D.
(2010). Parental stress is associated with
poor sleep quality in parents caring for
children with developmental disabilities.
Journal of Pediatric Psychology, 35(7), 728–
737. doi:10.1093/jpepsy/jsp093
*Gamaldo, A. A., Gamaldo, C. E., Allaire, J.
C., Aiken-Morgan, A. T., Salas, R. E.,
Szanton, S., & Whitfield, K. E. (2014). Sleep
complaints in older blacks: Do demographic
and health indices explain poor sleep quality
and duration?. Journal of Clinical Sleep
Medicine, 10(7), 725–731.
doi:10.5664/jcsm.3858
Hawkley, L. C., Lavelle, L. A., Berntson, G.
G., & Cacioppo, J. T. (2011). Mediators of
the relationship between socioeconomic
status and allostatic load in the Chicago
health, aging, and social relations study
(CHASRS). Psychophysiology, 48(8), 1134–
1145. doi:10.1111/j.1469-
8986.2011.01185.x
Hawkley, L. C., Masi, C. M., Berry, J. D., &
Cacioppo, J. T. (2006). Loneliness is a
unique predictor of age-related differences in
systolic blood pressure. Psychology and
Aging, 21(1), 152–164. doi:10.1037/0882-
7974.21.1.152
*Hayase, M., Shimada, M., & Seki, H.
(2014). Sleep quality and stress in women
with pregnancy-induced hypertension and
gestational diabetes mellitus. Women and
Birth, 27(3), 190–195.
doi:10.1016/j.wombi.2014.04.002
*Kashani, M., Eliasson, A., & Vernalis, M.
(2012). Perceived stress correlates with
disturbed sleep: A link connecting stress and
cardiovascular disease. Stress: The
International Journal on the Biology of
Stress, 15(1), 45–51. doi:
10.3109/10253890.2011.578266
*Ko, S. H., Chang, S. C., & Chen, C. H.
(2010). A comparative study of sleep quality
between pregnant and nonpregnant
Taiwanese women. Journal of Nursing
Scholarship, 42(1), 23–30.
doi:10.1111/j.1547-5069.2009.01326.x
Kurina, L. M., Knutson, K. L., Hawkley, L.
C., Cacioppo, J. T., Lauderdale, D. S., &
Ober, C. (2011). Loneliness is associated
with sleep fragmentation in a communal
society. Sleep, 34(11), 1519–1526.
doi:10.5665/sleep.1390
Lallukka, T., Sares-Jaske, L., Kronholm, E.,
Saaksjarvi, K., Lundqvist, A., Partonen, T.,
… Knekt, P. (2012). Sociodemographic and
socioeconomic differences in sleep duration
and insomnia-related symptoms in Finnish
adults. BMC Public Health, 12, 565.
doi:10.1186/1471-2458-12-565
Luyster, F. S., Strollo, P. J., Zee, P. C., &
Walsh, J. K. (2012). Sleep: A health
imperative. Sleep, 35(6), 727–34.
doi:10.5665/sleep.1846
McHugh, J. E., Casey, M. M., & Lawlor, B.
A. (2011). Psychosocial correlates of aspects
of sleep quality in community-dwelling Irish
older adults. Aging & Mental Health, 15(6),
749–755.
doi:10.1080/13607863.2011.562180
*McHugh, J. E., & Lawlor, B. A. (2013).
Perceived stress mediates the relationship
between emotional loneliness and sleep
quality over time in older adults. British
Journal of Health Psychology, 18(3), 546–
555. doi:10.1111/j.2044-8287.2012.02101.x
*Mellor, A., Waters, F., Olaithe, M.,
McGowan, H., & Bucks, R. S. (2014). Sleep
and aging: Examining the effect of
psychological symptoms and risk of sleep-
disordered breathing. Behavioral Sleep
Medicine, 12(3), 222–234.
doi:10.1080/15402002.2013.801343
Miró, E., Cano-Lozano, M. C., & Buela-
Casal, G. (2005). Sleep and quality of life.
Revista Colombiana de Psicología, 14, 11-
27.
Morin, C. M., Rodrigue, S., & Ivers, H.
(2003). Role of stress, arousal, and coping
skills in primary insomnia. Psychosomatic
Medicine, 65(2), 259–267.
doi:10.1097/01.psy.0000030391.09558.a3
Narendran, S., Nagarathna, R., Narendran,
V., Gunasheela, S., & Nagendra, H. R. R.
Advanced Research in Health, Education and Social Sciences: Towards a better practice
61
(2005). Efficacy of yoga on pregnancy
outcome. Journal of Alternative and
Complementary Medicine, 11(2), 237–244.
doi:10.1089/acm.2005.11.237
Nunes da Silva, J. M., Martins Costa, A. C.,
Waquim Machado, W., & Lopes Xavier, C.
(2012). Avaliação da qualidade de sono em
idosos não institucionalizados. ConScientiae
Saúde, 11(1), 29-36. doi:10.5585/
conssaude.v11n1.2940
*Okun, M. L., Tolge, M., & Hall, M. (2014).
Low socioeconomic status negatively affects
sleep in pregnant women. Journal of
Obstetric, Gynecologic, and Neonatal
Nursing : JOGNN / NAACOG, 43(2), 160–
167. doi:10.1111/1552-6909.12295
Patel, N. P., Grandner, M. A., Xie, D. W.,
Branas, C. C., & Gooneratne, N. (2010).
"Sleep disparity" in the population: Poor
sleep quality is strongly associated with
poverty and ethnicity. BMC Public Health,
11, 10:475. doi:10.1186/1471-2458-10-475
*Rocha, M. C. P. da, & Martino, M. M. F.
(2010). O estresse e qualidade de sono do
enfermeiro nos diferentes turnos
hospitalares. Revista da Escola de
Enfermagem Da USP, 44(2), 280–286.
doi:10.1590/S0080-62342010000200006
Sayar, K., Arikan, M., & Yontem, T. (2002).
Sleep quality in chronic pain patients.
Canadian Journal of Psychiatry-Revue
Canadienne de Psychiatrie, 47(9), 844–848.
Siegel, J. M. (2011). REM sleep: A
biological and psychological paradox. Sleep
Medicine Reviews, 15(3), 139–42.
doi:10.1016/j.smrv.2011.01.001
*Theadom, A., & Cropley, M. (2008).
Dysfunctional beliefs, stress and sleep
disturbance in fibromyalgia. Sleep Medicine,
9(4), 376–81. doi:10.1016/
j.sleep.2007.06.005
Van Reeth, O., Weibel, L., Spiegel, K.,
Leproult, R., Dugovic, C., & Maccari, S.
(2000). Interactions between stress and
sleep: From basic research to clinical
situations. Sleep Medicine Reviews, 4(2),
201–219. doi:10.1053/smrv.1999.0097
Wilcox, S., Brenes, G. A., Levine, D.,
Sevick, M. A., Shumaker, S. A., & Craven,
T. (2000). Factors related to sleep
disturbance in older adults experiencing knee
pain or knee pain with radiographic evidence
of knee osteoarthritis. Journal of the
American Geriatrics Society, 48(10), 1241–
1251.
