wileyonlinelibrary.com/journal/jch J Clin Hypertens. 2018;20:592–605.
©2017 Wiley Periodicals, Inc.
1 | INTRODUCTION
Patients with hypertension have been found to be more susceptible
to various cardiovascular diseases including stroke and coronary heart
Adequate sleep duration not only maintains body function,
but also prevents adverse cardiovascular outcomes. For instance, in-
adequate sleep has been associated with hypertension
from cardiovascular diseases.
Apart from sleep duration, sleep quality
is another important aspect of sleep, but its relationship with cardio-
vascular outcomes has received little attention.
One possible reason underlying the paucity of studies on sleep
quality concerns its complicated conceptualization. Sleep quality is a
composite of sleep indexes, including sleep duration and presence of
sleep problems, which can be measured objectively (eg, polysomnog-
raphy or actigraphy) or subjectively (eg, sleep diaries or self- reported
Objective sleep quality is categorized into a set of indexes
including awakenings, amount and percentage of sleep stages, rapid
eye movement latency, number of apneas or hypopneas, and periodic
movements of sleep.
Despite their precision in measurement, the ob-
jective indexes are not consolidated into a global sleep- quality index
based on their relative importance.
Although sleep measures resemble objective sleep indexes (eg,
awakenings during sleep and sleep disturbances), the subjective sleep
quality refers to the retrospective appraisal of the sleep experience
as recalled by the individual, which can be summarized into a global
For instance, the Pittsburgh Sleep Quality Index (PSQI)
encompasses sleep latency, sleep duration, habitual sleep efficiency,
sleep disturbances, use of sleeping medications, and daytime dysfunc-
tion in the previous month.
The PSQI is a popular and clinically ac-
cepted instrument of choice because of its high internal consistency
(α = 0.83), test- retest reliability (r = .85),
and moderate structural va-
lidity identifying patients with poor sleep quality in both clinical and
nonclinical populations (a global score >5 of 21).
Several reviews have
assessed the association between PSQI- measured sleep quality and
health outcomes including obesity
and glycemic control.
Studies conducted in Asia
have suggested that poor
subjective sleep quality is associated with significantly higher odds ratios
(ORs) of hypertension. Poor sleep has also been associated with signifi-
cantly higher levels of systolic blood pressure (SBP) and/or diastolic blood
pressure (DBP) in Asian
and European studies.
existing body of evidence is not entirely consistent, as insignificant asso-
ciations between poor sleep and blood pressure (BP) have been found
across different study regions, such as the American continent
This observation indicates that the relationship between sleep
quality and hypertension may vary across continents. In addition, sev-
eral studies have revealed that patients with hypertension have higher
Received: 26 September 2017
Revised: 27 November 2017
Accepted: 8 December 2017
Subjective sleep quality, blood pressure, and hypertension: a
Kenneth Lo BSc
| Brigitte Woo BN
| Martin Wong BSc
| Wilson Tam PhD
School of Public Health and Primary
Care, The Chinese University of Hong Kong,
New Territories, Hong Kong
Alice Lee Centre for Nursing Studies, Yong
Loo Lin School of Medicine, National
University of Singapore, Singapore
The Nethersole School of Nursing, The
Chinese University of Hong Kong, New
Territories, Hong Kong
Wilson Tam, PhD, Alice Lee Centre for Nursing
Studies, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore.
Sleep quality is an important aspect of sleep, but no meta- analysis has elucidated its
relationship with blood pressure (BP) and hypertension. A meta- analysis was con-
ducted in October 2016 using multiple databases, including Embase and Medline.
Studies that assessed subjective sleep quality and BP or hypertension were included.
Upon full- text evaluation, 29 articles from 45 041 patients were selected, of which 22
articles were included in the meta- analysis and seven were presented narratively. Poor
sleep quality was significantly associated with a greater likelihood of hypertension
(odds ratio, 1.48; P value = .01). Poor sleepers had higher average systolic BP (mean
difference = 4.37, P value = .09) and diastolic BP (mean difference = 1.25, P value = .32)
than normal sleepers without statistical significance. Patients with hypertension had
significantly worse sleep quality scores (mean difference = 1.51, P value < .01), while
BP dippers had significantly better scores (mean difference = −1.67, P value < .01).
The findings highlight the relationship between sleep quality and hypertension.