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Effect of respiratory pattern on automated clinical blood pressure measurement: an observational study with normotensive subjects

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Background It has been reported that deep breathing could reduce blood pressures (BP) in general. It is also known that BP is decreased during inhalation and increased during exhalation. Therefore, the measured BPs could be potentially different during deep breathing with different lengths of inhalation and exhalation. This study aimed to quantitatively investigate the effect of different respiratory patterns on BPs. Methods Forty healthy subjects (20 males and 20 females, aged from 18 to 60 years) were recruited. Systolic and diastolic BPs (SBP and DBP) were measured using a clinically validated automated BP device. There were two repeated measurement sessions for each subject. Within each session, eight BP measurements were performed, including 4 measurements during deep breathing with different respiratory patterns (Pattern 1: 4.5 s vs 4.5 s; Patter 2: 6 s vs 2 s; Pattern 3: 2 s vs 6 s; and Pattern 4: 1.5 s vs 1.5 s, respectively for the durations of inhalation and exhalation) and additional 4 measurements from 1 min after the four different respiratory patterns. At the beginning and end of the two repeated measurement sessions, there were two baseline BP measurements under resting condition. Results The key experimental results showed that overall automated SBP significantly decreased by 3.7 ± 5.7 mmHg, 3.9 ± 5.2 mmHg, 1.7 ± 5.9 mmHg and 3.3 ± 5.3 mmHg during deep breathing, respectively for Patterns 1, 2, 3 and 4 (all p < 0.001 except p < 0.05 for Pattern 3). Similarly, the automated DBPs during deep breathing in pattern 1, 2 and 4 decreased by 3.7 ± 5.0 mmHg, 3.7 ± 4.9 mmHg and 4.6 ± 3.9 mmHg respectively (all p < 0.001, except in Pattern 3 with a decrease of 1.0 ± 4.3 mmHg, p = 0.14). Correspondingly, after deep breathing, automated BPs recovered back to normal with no significant difference in comparison with baseline BP (all p > 0.05, except for SBP in Pattern 4). Conclusions In summary, this study has quantitatively demonstrated that the measured automated BPs decreased by different amounts with all the four deep breathing patterns, which recovered back quickly after these single short-term interventions, providing evidence of short-term BP decrease with deep breathing and that BP measurements should be performed under normal breathing condition.
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R E S E A R C H Open Access
Effect of respiratory pattern on automated
clinical blood pressure measurement: an
observational study with normotensive
subjects
Natalia Herakova
1
, Nnenna Harmony Nzeribe Nwobodo
1,2
, Ying Wang
1
, Fei Chen
3
and Dingchang Zheng
1*
Abstract
Background: It has been reported that deep breathing could reduce blood pressures (BP) in general. It is also
known that BP is decreased during inhalation and increased during exhalation. Therefore, the measured BPs could
be potentially different during deep breathing with different lengths of inhalation and exhalation. This study aimed
to quantitatively investigate the effect of different respiratory patterns on BPs.
Methods: Forty healthy subjects (20 males and 20 females, aged from 18 to 60 years) were recruited. Systolic and
diastolic BPs (SBP and DBP) were measured using a clinically validated automated BP device. There were two repeated
measurement sessions for each subject. Within each session, eight BP measurements were performed, including 4
measurements during deep breathing with different respiratory patterns (Pattern 1: 4.5 s vs 4.5 s; Patter 2: 6 s vs 2 s;
Pattern 3: 2 s vs 6 s; and Pattern 4: 1.5 s vs 1.5 s, respectively for the durations of inhalation and exhalation) and
additional 4 measurements from 1 min after the four different respiratory patterns. At the beginning and end of the
two repeated measurement sessions, there were two baseline BP measurements under resting condition.
Results: The key experimental results showed that overall automated SBP significantly decreased by 3.7 ± 5.7 mmHg,
3.9 ± 5.2 mmHg, 1.7 ± 5.9 mmHg and 3.3 ± 5.3 mmHg during deep breathing, respectively for Patterns 1, 2, 3 and 4
(all p< 0.001 except p< 0.05 for Pattern 3). Similarly, the automated DBPs during deep breathing in pattern 1, 2 and 4
decreased by 3.7 ± 5.0 mmHg, 3.7 ± 4.9 mmHg and 4.6 ± 3.9 mmHg respectively (all p< 0.001, except in Pattern 3 with
a decrease of 1.0 ± 4.3 mmHg, p= 0.14). Correspondingly, after deep breathing, automated BPs recovered back to
normal with no significant difference in comparison with baseline BP (all p> 0.05, except for SBP in Pattern 4).
Conclusions: In summary, this study has quantitatively demonstrated that the measured automated BPs decreased by
different amounts with all the four deep breathing patterns, which recovered back quickly after these single short-term
interventions, providing evidence of short-term BP decrease with deep breathing and that BP measurements should be
performed under normal breathing condition.
Keywords: Blood pressure, Breathing pattern, Diastolic, Exhalation, Fast-deep breathing, Inhalation, Respiratory pattern,
Slow-deep breathing, Systolic
* Correspondence: dingchang.zheng@anglia.ac.uk
1
Health and Wellbeing Academy, Faculty of Medical Science, Anglia Ruskin
University, Chelmsford, UK
Full list of author information is available at the end of the article
© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Herakova et al. Clinical Hypertension (2017) 23:15
DOI 10.1186/s40885-017-0071-3
Background
The importance of accurate blood pressure (BP) meas-
urement is without doubt. According to a major review
in the Journal of the American Medical Association
(JAMA), a 5 mmHg error would result in 21 million
Americans being denied treatment or 27 million being
exposed to unnecessary treatment, depending on the dir-
ection of the error [1]. Unfortunately, BP measurement
is still one of the most poorly performed diagnostic
measurements in real clinical practice [2]. It is gener-
ally accepted that BP measurement inaccuracies are as-
sociated with the measurement conditions, including
incorrect patient posture, incorrect arm position and
incorrect cuff position and size [35], and also associ-
ated with short-term physiological changes during the
measurement leading to within-subject BP variability
[6]. It has been widely accepted that respiration is one
of the key factors affecting short-term physiological
changes in BP and therefore leading to potential meas-
urement error [2].
Respiration is the natural physiological mechanism
during which air is inhaled into the lungs and then ex-
haled via the nose or mouth. Normal breathing is invol-
untary and rhythmic, and two processes are involved
during breathing are inspiration (or inhalation) and ex-
piration (or exhalation) [7, 8]. During inspiration with
oxygen inhaled into the body, the intercostal muscles
contract, expanding the ribcage and the diaphragm con-
tracts, pulling down to increase the volume of the chest.
This lowers the pressure inside the thorax and gets air
sucked into the lungs. During exhalation with carbon di-
oxide exhaled out of the body, the intercostal muscles
relax and lower the ribs downward, causing the diaphragm
to relax and move back upwards. This causes a decrease
in thorax volume, which as a result, increases the pressure
inside the thorax.
Several published studies have shown that respiration
influences both short-term and long-term systolic and
diastolic blood pressures (SBP and DBP) measured by
different techniques [6, 914]. For instance, it has been
reported by Zheng et al. [6] that, with regular slow and
deep breathing, both manual auscultatory SBP and DBP
decreased significantly by 4.4 and 4.8 mmHg respect-
ively, in comparison with normal breathing. On the
other hand, the physiological mechanisms of respiration
process indicate that BP is decreased during inhalation
and increased during exhalation [15]. Since a single BP
measurement may take more than one or two normal
respiratory cycles, the measured BPs could be potentially
different with different types of deep breathings where
various lengths of inhalation and exhalation are involved.
To the best of our knowledge, there is little quantitative
information available on the effect of different respira-
tory patterns on measured BPs.
The aim of this research was to quantitatively investi-
gate the effect of different breathing patterns on BPs in
comparison with baseline BP measurement.
Methods
Subjects
Forty healthy normotensive subjects, 20 males and 20 fe-
males, aged 1860, were recruited. The requirements of
inclusion criteria included: normal healthy individual,
age range 1860 years old, with SBP < 140 mmHg and
DBP < 90 mmHg. Participants with known hypertension
and antihypertensive medical treatment, or cardiovascu-
lar disease, such as ischaemic heart disease, congestive
heart failure, chronic atrial fibrillation, renal failure and
previous stroke, were excluded. Additionally, if the initial
BP measurement showed SBP > 140 mmHg and DBP >
90 mmHg, these participants were also excluded. Subjects
demographic information, including age, weight, height
and arm circumference are summarized in Table 1.
This study has been reviewed and approved by the
Faculty Research Ethics Panel, Faculty of Medical Sci-
ence, Anglia Ruskin University. The investigation con-
formed with the Declaration of Helsinki, and all subjects
gave their written informed consent to participate in the
study.
Blood pressure measurement protocol and procedure
The measurements were conducted in a quiet room at
Anglia Ruskin University. All the subjects were asked to
rest in a seated position for at least 5 min before the for-
mal BP measurement. SBP, DBP were measured from
the left arm using a suitable cuff matched to individual
arm circumference (adult 2434 cm; large adult 3441 cm)
by a clinically validated automated BP device (HBPM
Omron, M6 Comfort). The HR value was also obtained
during each measurement from the device. The BP meas-
urement procedure followed the Measurement Guideline
from the European Society of Hypertension [16].
A mobile phone application (Paced Breathing, Android
App on Google Play), which was designed to adjust the
duration of inhalation and exhalation and display the
visual pattern on the screen (see Fig. 1b), was used for
the subjects to follow the different respiratory patterns
and synchronize their breathing with the defined patterns.
All subjects were given the opportunity to practice and be
Table 1 Demographic data of subjects studied
Subject information Minimum Maximum Mean Standard
deviation
Age 20 59 37 10
Height (cm) 151 183 170 9
Weight (kg) 51 108 74 14
Arm circumference (cm) 24 40 31 4
Herakova et al. Clinical Hypertension (2017) 23:15 Page 2 of 7
familiar with these respiratory patterns before the formal
experiment.
There were two repeated measurement sessions for each
subject (see Fig. 1a). At the beginning and end of the two
sessions, there were two baseline BP and HR readings
under resting condition. Within each session, eight BP
and HR measurements were performed, including 4
measurements during deep breathing using four differ-
ent respiratory patterns and additional 4 measurements
from 1 min after the four different patterns of deep
breathing. During deep breathing with a certain re-
spiratory pattern, before the automated BP measure-
ment started, the subjects were asked to breathe three
respiratory cycles, and this continued until the BP
measurement completed. The order of the sequence of
the four respiratory patterns was randomised between
subjects. As shown in Fig. 1b), the details of the four
respiratory patterns were:
Pattern 1: slow deep breathing with 4.5 s of inhalation
and 4.5 s exhalation;
Pattern 2: long inspiration followed by short expiration
with 6 s inhalation and 2 s exhalation;
Pattern 3: short inspiration followed by long expiration
with 2 s inhalation and 6 s exhalation;
Pattern 4: fast deep breathing with 1.5 s inhalation and
1.5 s exhalation.
Data and statistical analysis
All recorded BP and HR data were stored in Excel
Spreadsheet, then transferred and analysed in statistical
software SPSS 20.0. The means and standard deviations
(SDs) of SBP, DBP and HR were calculated separately for
the baseline, during four different respiratory patterns,
and after deep breathings. Analysis of variance (ANOVA)
was then performed to investigate the measurement re-
peatability and the effect of respiratory pattern on BP and
HR measured during and after deep breathing. The post-
hoc multiple comparison in the ANOVA test was used to
compare the differences in BP and HR between respiratory
patterns. A pvalue below 0.05 was considered statistically
significant.
Results
BP and HR measurement repeatability
ANOVA analysis showed that baseline BP and HR at the
beginning and end of the main measurement sessions
were repeatable (p=0.4for SBP,p=0.5 for DBPandp=0.6
for HR). Furthermore, BP and HR measurements during
and after deep breathing were also repeatable between the
repeat sessions (all p> 0.1). As the BP and HR measure-
ments were repeatable, their average values from the two
repeat measurements were used as a reference value for
each subject.
HR changes during and after deep breathing in
comparison with baseline
Figure 2 shows the HRs measured during and after deep
breathing. In comparison with the Baseline, it can be
seen that HR during deep breathing increased signifi-
cantly in Patterns 3 and 4 (69.4 ± 9.3 and 70.1 ± 8.7 vs
67.1 ± 8.5 beats/min, both p< 0.01), but not in Patterns 1
and 2. After deep breathing, all the HRs recovered back
to normal with no statistically significant HR difference
in comparison with Baseline (all p> 0.2).
Fig. 1 aBP measurement procedure. Participants were given 5 min before the initial BP was measured. During deep breathing, before the automated
BP measurements started, 3 respiratory cycles were performed, and this continued until the completion of BP measurement. bIllustration of deep
breathing with four different respiratory patterns. Pattern 1: slow breathing (4.5 s 4.5 s); Pattern 2: long inspiration followed by short expiration
(6s2 s); Pattern 3: short inspiration followed by long expiration (2s6 s); Pattern 4: fast breathing (1.5 s 1.5 s)
Herakova et al. Clinical Hypertension (2017) 23:15 Page 3 of 7
SBP changes during and after deep breathing in
comparison with baseline
Figure 3a) shows SBP measured during and after deep
breathing. It can be seen that SBPs measured during
deep breathing were significantly decreased in compari-
son with the Baseline. Specifically, as shown in Fig. 4a)
and Table 2, SBP in Patterns 1, 2 and 4 decreased by
3.7 ± 5.7 mmHg, 3.9 ± 5.2 mmHg and 3.3 ± 5.3 mmHg
respectively (all p< 0.001) and SBP in Pattern 3 decreased
by 1.7 ± 5.9 mmHg (p< 0.05). It was also observed that
SBP after deep breathing did not change significantly in
comparison with Baseline in Pattern 1, 2, 3 (decreased by
1.0 ± 4.2 mmHg, 1.1 ± 3.5 mmHg, 1.2 ± 4.8 mmHg, with
p>0.05).
DBP changes during and after deep breathing in
comparison with baseline
Figure 3b) shows DBP measured during and after deep
breathing. In comparison with the Baseline, DBP in
Patterns 1, 2 and 4 during deep breathing decreased
significantly by 3.7 ± 5.0 mmHg, 3.7 ± 4.9 mmHg and
4.6 ± 3.9 mmHg respectively (all p< 0.001). DBP in Pat-
tern 3 did not decrease significantly in comparison with
Baseline (mean difference of 1.0 ± 4.3 mmHg; p= 0.14).
DBP after deep breathing did not show significant
changes in comparison with Baseline (with the mean
decreased of 0.09 ± 4.15 mmHg, 0.14 ± 2.71 mmHg,
0.45 ± 2.71 mmHg and 0.46 ± 3.16 mmHg, respectively
forPatterns1,2,3and4;allp>0.05).
Fig. 2 Means + SDs of HR measured during and after deep breathing, separately for different respiratory patterns.
**
p<0.001;
*
p<0.05 in
comparison with baseline HR
Fig. 3 Means + SDs of systolic (a) and diastolic (b) blood pressures measured during and after deep breathing, separately for different respiratory
patterns.
**
p< 0.001;
*
p<0.05 in comparison with baseline BP
Herakova et al. Clinical Hypertension (2017) 23:15 Page 4 of 7
Discussion and conclusions
This study quantitatively demonstrated the effect of dif-
ferent deep breathing patterns (with different durations
of inhalation and exhalation) on automated BPs. To the
best of our knowledge, this was the first study to com-
prehensively compare the short-term effect of different
breathing patterns on automated BPs.
According to the results of the present study, Pattern
1 (slow and deep breathing with 4.5 s inhalation and
4.5 s exhalation) achieved a significant decrease in both
automated SBP and DBP by 3.7 ± 5.7/3.7 ± 5.0 mmHg,
respectively. These results agreed with the findings from
previous studies, where it has been concluded that slow
and deep breathing could reduce BP [6, 10, 17, 18]. Some
of the published studies mainly focused on the long-term
effect, while the others on the short-term effect on BP
variability. Bhavanani, et al. [17] applied slow and deep
breathing with equal duration of inhalation and exhalation
at the rate of 6 breaths/min and achieved BP reduction in
hypertensive patients with 5 min of practice. With slow
deep breathing, BPs are reduced via increased baroreflex
sensitivity, which regulates BP by controlling heart rate,
sympathetic activity and chemoreflex activation [19]. In
addition, any slight deviation in the oxygen content in the
brain may affect the cardiovascular function. During slow
and deep breathing, oxygenation allows the body to absorb
its full oxygen quota, which relaxes the brain and calms
the cardiovascular system, resulting in reduced stress and
decreased BP.
This study also showed significant decrease in automated
SBP/DBP (3.9 ± 5.2 mmHg/3.7 ± 4.9 mmHg, respectively)
in Pattern 2 with 6 s inhalation and 2 s exhalation. This
Fig. 4 Decrease of systolic (a) and diastolic (b) blood pressures (SBP and DBP) during and after deep breathing in comparison with baseline. The
results for different respiratory patterns are given separately.
**
p< 0.001;
*
p< 0.05 in comparison with baseline BP
Table 2 Means ± SDs of systolic and diastolic blood pressures (SBP and DBP) measured during and after deep breathing and their
differences in comparison with baseline BPs
During breathing BP decrease After breathing BP decrease
SBP
(mmHg)
Baseline 111.5 ± 10.5
Pattern 1 107.8 ± 11.5 3.7 ± 5.7
**
110.4 ± 10.7 1.0 ± 4.2
Pattern 2 107.6 ± 12.2 3.9 ± 5.2
**
110.3 ± 10.3 1.1 ± 3.5
Pattern 3 109.7 ± 13.0 1.7 ± 5.9
*
110.3 ± 12.2 1.2 ± 4.8
Pattern 4 108.2 ± 11.3 3.3 ± 5.3
**
109.5 ± 10.2 1.9 ± 3.5
*
DBP
(mmHg)
Baseline 74.4 ± 8.2
Pattern 1 70.7 ± 9.0 3.7 ± 5.0
**
74.4 ± 9.0 0.1 ± 4.1
Pattern 2 70.7 ± 8.0 3.7 ± 4.9
**
74.5 ± 8.6 0.1 ± 3.3
Pattern 3 73.3 ± 9.2 1.0 ± 4.3 73.9 ± 8.8 0.5 ± 2.7
Pattern 4 69.7 ± 8.2 4.6 ± 3.9
**
73.9 ± 8.3 0.5 ± 3.2
**
p< 0.001;
*
p< 0.05
Herakova et al. Clinical Hypertension (2017) 23:15 Page 5 of 7
could be explained by the temporary physiological effect of
decreasing stroke volume during long standing inhalation
or widened thoracic for downward movement of dia-
phragm [20]. It is also noticed that there was no significant
HR change with this breathing pattern, indicating the po-
tential involvement of sympathetic de-activation and that
the BP lowering effect could be persistent during deep
exhalation.
The respiratory Pattern 3 involved 2 s inhalation and
6 s exhalation. Although some published studies used
similar pattern and achieved a positive BP reduction [10,
19, 21], the results of the present study showed that this
pattern only achieved significant automated SBP de-
crease (1.7 ± 5.9 mmHg), but for DBP (1.0 ± 4.3 mmHg).
This could be explained by the physiology of long exhal-
ation which relates to a relaxation of diaphragm and an
increase of intrathoracic pressure, refilling the left ven-
tricle with blood and causing BP to increase. Pattern 4
was the only patter where the fast breathing (1.5 s inhal-
ation and 1.5 s exhalation) was used. The HR was sig-
nificantly increased with this pattern. Although many
participants complained of light dizziness during the ex-
periment, significant decrease was still observed in SBP/
DBP (3.3 ± 5.3/4.6 ± 3.9 mmHg, respectively).
Overall, the four respiratory patterns applied in this
study all reduced the short-term BPs by different
amounts. It is noticed that the participants felt more
comfortable to follow some patterns than the others, in-
dicating different physiological mechanisms could be in-
volved in these patterns. There is also possibility of this
BP lowering effect might be from self-noticeof own
respiration or concentration on own respiration regard-
less of respiratory pattern. Published report has showed
transcendental meditation is associated with reductions
of SBP and DBP [22]. Similar BP reduction was observed
in both normotensive and hypertensive individuals. For a
better understanding of their underlying mechanisms,
more data about BP reduction efficacy of self-notice or
concentration on spontaneous respiration is required in
a future study.
In addition, this study also showed that the measured
BPs recovered back to normal 1 min after the deep
breathings, with no significant difference in comparison
with Baseline. The only exception was SBP in Pattern 4
(with mean difference of BP by 1.9 ± 3.5 mmHg), which
can be explained by the fact that it takes longer for the
cardiovascular circulation to be stabilised. The results
provided evidence that, although short-term BP variability
was produced during deep breathing, both BP and HR
could recover quickly back to normal, suggesting that it is
better to measure BP under resting condition with normal
breathing pattern to achieve reliable BP values.
One of the limitations in this study is the fact that it was
not established whether the participants should inhale/
exhale with mouth or nose [17, 20, 23]. A comparison of
the effect of using different breathing approaches on BPs
could be included in a future study. Next, only the short-
term effect of deep breathing on BPs was investigated. The
long-term benefit of each breathing pattern with regular
practice should be investigated, to confirm whether rou-
tinely performed sessions of breathing exercises may lead
to a sustained reduction in BP for exploring its potential
clinical application. Furthermore, this preliminary study
was conducted only on normotensive subjects. The neuro-
humoral balance could be de-ranged in patients with
hypertension. Therefore, it is not guaranteed whether
similar results of this research could be achieved with
hypertensive patients or patients with other diseases.
It should be also noted that the measured BPs in this
study were from a clinically validated automated BP de-
vice. The automated BP device used here is based on
oscillometric technique, where BPs are normally esti-
mated from the global envelope of the oscillometric
pulses recorded from the whole period of the measure-
ment that covers several respiratory cycles. Since the
measuring principle of manual auscultatory technique is
different with the oscillometric technique, the effect of
different respiratory patterns on manual auscultatory BPs
could be different, depending on which phase (inspiration
or expiration) the SBP and DBP determinations are made
[8]. The potential different effects of deep breathing on
manual and automated BPs are worth further investiga-
tion. It would be also useful to investigate the beat-to-beat
BP changes in association with deep breathing with differ-
ent respiratory patterns.
In summary, this study has quantitatively demon-
strated that the measured automated BPs decreased by
different amounts with all the four deep breathing pat-
terns, which recovered back quickly after these single
short-term interventions, providing scientific evidence
of short-term BP decrease with deep breathing and that
BP measurements should be performed under normal
breathing condition.
Abbreviations
BP: Blood pressure; DBP: Diastolic blood pressure; SBP: Systolic blood
pressure; SD: Standard deviation
Acknowledgements
Not applicable.
Funding
None.
Availability of data and materials
Data is available in a database from the corresponding author on reasonable
request.
Authorscontributions
DZ, NH and FC conceived the idea and contributed to study design. NH
conducted the literature searches. NH, HNN and YW evaluated the
methodological quality, interpreted the data and made the analysis, having
full access to all data in this study and taking responsibility for the integrity
Herakova et al. Clinical Hypertension (2017) 23:15 Page 6 of 7
and accuracy of the data analysis. DZ and FC reviewed and commented on
the article. All authors read and approved the final manuscript.
Competing interests
The authors declare that they have no competing interests.
Consent for publication
Not applicable. No individual data in any form is disclosed.
Ethics approval and consent to participate
Ethical approval was obtained from the Faculty Research Ethics Panel,
Faculty of Medical Science, Anglia Ruskin University. The written and
informed consent was obtained from all participants before they were
eligible into the study.
PublishersNote
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
Author details
1
Health and Wellbeing Academy, Faculty of Medical Science, Anglia Ruskin
University, Chelmsford, UK.
2
Department of Computer Engineering, faculty of
Engineering, Enugu State University of Science and Technology, Enugu,
Nigeria.
3
Department of Electrical and Electronic Engineering, Southern
University of Science and Technology, Shenzhen, China.
Received: 8 December 2016 Accepted: 11 April 2017
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Herakova et al. Clinical Hypertension (2017) 23:15 Page 7 of 7
... The aim is to realize a device capable of carrying out real-time continuous monitoring of multiple physiological parameters, in a non-invasive manner. In this paper, we show the effects of deep breathing on photoplethysmographic waveforms, since it has been demonstrated that deep breathing produces strong effects on heart rate and blood pressure [28]- [31]. The preliminary results are promising. ...
... The trends depicted in the figure can be explained by the fact that during exhalation the blood volume brought by veins to the left atrium is higher, with augmented stroke volume, followed by an increase of the systolic pressure; the opposite phenomena are observed during inhalation. The effects are more evident during deep breathing, and this may be related to the widely known fact that deep breathing produces noteworthy consequences on heart rate, stroke volume and blood pressure [28]- [31]. Figure 7 shows the trend of the Pulse Arrival Time during a 200-s interval. ...
... Besides extracting the essential BP features, the raw Bio-Z is rich with additional data that can be used to monitor other vital signs, such as breathing respiration rate 30 . Breathing is facilitated by lung volume increase, which in turn imposes undulating internal pressure onto surrounding objects, exerting a substantial influence on arterial BP 30,37,48 . Supplementary Fig. 17 summarizes the Bio-Z extracted respiration rate data, fast Fourier transformation analysis and time trace of the respiration rate changes measured continuously with no additional signal recording. ...
Article
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Continuous monitoring of arterial blood pressure (BP) in non-clinical (ambulatory) settings is essential for understanding numerous health conditions, including cardiovascular diseases. Besides their importance in medical diagnosis, ambulatory BP monitoring platforms can advance disease correlation with individual behaviour, daily habits and lifestyle, potentially enabling analysis of root causes, prognosis and disease prevention. Although conventional ambulatory BP devices exist, they are uncomfortable, bulky and intrusive. Here we introduce a wearable continuous BP monitoring platform that is based on electrical bioimpedance and leverages atomically thin, self-adhesive, lightweight and unobtrusive graphene electronic tattoos as human bioelectronic interfaces. The graphene electronic tattoos are used to monitor arterial BP for >300 min, a period tenfold longer than reported in previous studies. The BP is recorded continuously and non-invasively, with an accuracy of 0.2 ± 4.5 mm Hg for diastolic pressures and 0.2 ± 5.8 mm Hg for systolic pressures, a performance equivalent to Grade A classification. Self-adhesive bioimpedance graphene electronic tattoos enable accurate continuous blood pressure monitoring.
... [55] In the present study, all recordings were done in supine posture. Music combined with guided breathing exercises has shown better control of physiological parameters in a few studies, [56,57] while deep breathing exercise did not augment the benefit of music in reducing BP. [58] Among the various mechanisms dopamine released in the striatal system, on listening to pleasurable songs, is said to be involved in autonomic regulation. [59] The strengths of the current study are that, to the best of our knowledge, for the 1 st time, an Indian melodic scale has been studied as an acoustic stimulus systematically and scientifically, through a randomised trial (avoiding different types of bias), among normal healthy individuals. ...
Article
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Objectives Listening to music is entertaining but also has different health benefits. Music medicine involves passive listening to music, while music therapy involves active music-making. Indian music is broadly classified into Hindustani and Carnatic music, each having its system of musical scales ( ragas ). Scientific studies of Indian music as an intervention are meagre. The present study determines the effect of passive listening to one melodic scale of Indian music on cardiovascular electrophysiological parameters. Materials and Methods After informed consent, healthy individuals aged 18–30 years of either gender were recruited and randomly divided into two groups ( n = 34 each). Group A was exposed to passive listening to the music intervention (Hindustani melodic scale elaboration [ Bhimpalas raga alaap ]), while Group B received no intervention except for a few natural sounds (played once in every 2 min). Blood pressure (BP, systolic, SBP; diastolic, DBP) and electrocardiogram in Lead II were recorded with each condition lasting for 10 min (pre, during and post). Heart rate variability (HRV) analysis was done. Data were analysed using SPSS 18.0 version and P ≤ 0.05 was considered significant. Results In Group A, the SBP did not change during the intervention but increased mildly after the intervention ( P = 0.054). The DBP increased in both the groups during the intervention, significant in Group A ( P = 0.009), with an increase of 1.676 mmHg ( P = 0.012) from pre-during and 1.824 mmHg ( P = 0.026) from pre-post intervention. On HRV analysis, mean NN interval increased and HR reduced in both the groups, but was significant only in Group B ( P = 0.041 and 0.025, respectively). In Group A, most of the HRV parameters were reduced during music intervention that tended to return toward baseline after the intervention, but the change was statistically significant for total power ( P = 0.031) and low frequency ( P = 0.013); while in Group B, a consistent significant rise in parasympathetic indicators (SDNN, RMSSD, total power and HF [ms ² ]) over 30 min was observed. Conclusion Unique cardiovascular effects were recorded on passive listening to a particular Indian music melodic scale. The scale, raga Bhimpalas , produced a mild arousal response. This could be due to attention being paid to the melodic scale as it was an unfamiliar tune or due to the features of this melodic scale that led to an arousal or excitation response. In contrast, the control group had only a relaxation response. Exploring electrophysiological effects of different genres, melodic scales and their properties after familiarising with the music may thus be illustrative.
... Literature had reported the activation of the PNS due to hypoventilation or other relaxation technique linked to respiration, also known as respiratory sinus arrhythmia (RSA) [34,37,38]. Herein, no significant variation was observed in respiration and its parameters during 6-degree HDT, which shows the absence of RSA. ...
Article
In the study, quantitative analysis was done to identify the interaction among cardiac, vascular and respiratory signals for 6-degree head-down tilt (HDT) microgravity analogue. This HDT shifts the blood volume towards the thoracic cavity of the human body. The linear and non-linear domain analyses are based on coherence techniques that are used to analyse these cardiovascular responses. But they lack to measure the information flow and coupling changes that occurred during HDT. The present study applied an information domain approach for the investigation of non-linear causality to the heart rate variability, systolic blood pressure and respiration measured during HDT. It was hypothesized that the HDT will demonstrate alteration in cardiac, vascular and respiratory parameters. Twenty healthy subjects were inspected each for 10 min at supine rest and HDT. The responses were significant for cardiac and vascular but not for the respiratory system during HDT. It was observed that during HDT, the parasympathetic nervous system activated and increased the effect of vascular on the cardiac. The effect of respiration on either vascular or cardiac was not significant, therefore the variation and coupling observed in the vascular and cardiac systems are solely because of HDT. The results of this study support the hypothesis and revealed that the HDT altered the autonomic function parameters. It can be concluded that the HDT increases the parasympathetic activity and cardiovascular interaction as well as confirmed the usefulness of conditional entropy for coupling analysis.
... It has been reported that the triggering of the PNS due to slow breathing or hypoventilation or other relaxing techniques related to respiration, also known as respiratory sinus arrhythmia, can interfere with cardiovascular functioning (Faes et al., 2012;Herakova et al., 2017;Zheng et al., 2012). During the 6-degree HDT, no major difference in respiration parameters were detected, indicating the absence of respiratory sinus arrhythmia. ...
Article
Prolonged exposure to microgravity causes physiological deconditioning in humans. Herein, a novel designed countermeasure gravitational load modulation bodygear has been developed to deal with the ill effects of the microgravity environment. The bodygear is designed to provide the wearer an axial loading from the shoulder to the feet that simulate Earth's gravity. The present study aims to evaluate the effect of bodygear on cardiac, vascular and respiratory systems during head-down tilt (HDT) microgravity analogue. In this, 30 healthy male subjects have volunteered and their average age, height and weight were 24.56 ± 3.87yr, 168.4 ± 9.17cm and 65.9 ± 10.51Kg respectively. The physiological signals such as electrocardiogram (ECG), blood pressure (BP) and respiration were recorded non-invasively using Biopac MP100. The signals were sampled at 1,000 Hz and processed using MATLAB 2018b. The signals were analysed in linear well as non-linear domains. The ECG and BP were used to derive R-R interval (RRI) and systolic blood pressure (SBP). The respiration time series (RSP) was derived by extracting R-peaks from the ECG signal and using these peaks to find the respiration amplitude. The non-linear domain analysis was used for the detection and quantification of information flow among the recorded signals. Repeated measure analysis of variance with Bonferroni post-hoc paired t-test was used for statistical analysis with the p<0.05. The experimental results show that the 6-degree HDT activates the parasympathetic system and decreased the RRI effect on SBP (p=0.005). Interestingly with the bodygear usage, the sympathetic system activated, mean RRI decreased (p=0.018) and blood pressure increased (p=0.031) as compared to baseline. Further, it was also observed that the effect of RRI on SBP (p=0.029) and SBP on RRI (p=0.012) was increased with bodygear as compared to HDT without bodygear. The conditional entropy technique aided in analyzing the effect of bodygear on information flow variation in the cardiovascular system of the human body.
... The RSA has also been suggested to index CVA [80][81][82] and has been used in previous research investigating a similar research question [64]. Finally, future research should also consider investigating the inhalation/exhalation ratio at different breathing frequencies [64,68,83] and take into account the effects on other cardiovascular parameters, such as baroreflex sensitivity [84] and blood pressure [85]. Authors should discuss the results and how they can be interpreted from the perspective of previous studies and of the working hypotheses. ...
Article
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Slow-paced breathing has been shown to enhance the self-regulation abilities of athletes via its influence on cardiac vagal activity. However, the role of certain respiratory parameters (i.e., inhalation/exhalation ratio and presence of a respiratory pause between respiratory phases) still needs to be clarified. The aim of this experiment was to investigate the influence of these respiratory parameters on the effects of slow-paced breathing on cardiac vagal activity. A total of 64 athletes (27 female; Mage = 22, age range = 18–30 years old) participated in a within-subject experimental design. Participants performed six breathing conditions within one session, with a 5 min washout period between each condition. Each condition lasted 5 min, with 30 respiratory cycles, and each respiratory cycle lasted 10 s (six cycles per minute), with inhalation/exhalation ratios of 0.8, 1.0, 1.2; and with or without respiratory pauses (0.4 s) between respiratory phases. Results indicated that the root mean square of successive differences (RMSSD), a marker of cardiac vagal activity, was higher when exhalation was longer than inhalation. The presence of a brief (0.4 s) post-inhalation and post-exhalation respiratory pause did not further influence RMSSD. Athletes practicing slow-paced breathing are recommended to use an inhalation/exhalation ratio in which the exhalation phase is longer than the inhalation phase.
... Breathing techniques such as mantra breathing are relaxation techniques that can alleviate certain mild forms of arterial hypertension. Yoga or other relaxation techniques can also be used to influence systolic and diastolic blood pressure [2,3,4,5,6,7]. ...
Article
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Objective: Slow breathing is a relaxation exercise recommended for lowering blood pressure (BP). Biofeedback may improve patient adherence and enhance BP lowering effects. Since the pulse arrival time (PAT) is inversely proportional to BP, it can be used to estimate BP changes. Approach: In this pilot study, 30 patients (age 62.9 (SD 7.7) years, 11 F/19 M, Sys. BP 133.0 (SD 17.1) mmHg, Dia. BP 83.8 (SD 10.6) mmHg) performed a device-guided slow breathing exercise. PAT was measured by ECG and plethysmography and immediately presented to the patient, and respiratory sinus arrhythmia (RSA) was calculated retrospectively to measure the adherence to the instructed respiratory rate. Main results: Respiratory rate was 13.6 (SD 1.9) bpm at baseline and 5.4 (SD 1.0) bpm during guided breathing. PAT continuously and progressively increased from 231.5 (SD 20.3) to 237.3 (SD 18.5) ms (p [Formula: see text] 0.001). The median deviation of RSA from the guided respiratory rate was 0.06 (IQR 0.19) bpm. In three patients, a deviation of > 0.20 bpm was detected, and two of them showed no increase in PAT. In total, 25 patients responded with increase in PAT. Significance: In this pilot study we have shown that biofeedback of PAT and RSA are feasible and can further improve motivation and adherence. Furthermore, we have shown that the exercise increased PAT, which indicates a reduction in BP. Due to its ease of use, this method is ideal for home use and self-monitoring.
... Biobehavioral therapies usually result in positive health change, and studies have shown an impact on those diagnosed with hypertension (Cernes & Zimlichman, 2017;Herakova et al., 2017;Jones et al., 2015;Landman et al., 2014;Li et al., 2018;Mahtani et al., 2016;Van Hateren et al., 2014;Zhang et al., 2016). BF incorporates technology and selfmanagement and can help to meet young adults' health promotion needs (Lehrer et al., 2013). ...
Article
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Purpose This study explored the experiences of young adults who participated in biofeedback training and reported a family history of cardiovascular disease. Design A qualitative descriptive study design was used. Method Private semistructured interviews were conducted on a purposive sample. Young adults ( N = 9) were interviewed about their experiences using paced breathing biofeedback training with continuous blood pressure monitoring. Codes were identified across the sample with common themes recorded. Findings Data analysis yielded four themes: skeptical inquisition, tangible impression, positive health impact, and motivation. Prior to using biofeedback, participants were extremely skeptical of the training. However, all participants found it useful for health maintenance and stress reduction. Conclusions Biofeedback therapy may be a promising alternative and holistic approach to managing blood pressure and psychological stress in young adults. This is a complementary approach that nurses can incorporate when caring for the holistic needs of young adults.
Article
Objectives: It is clinically important to evaluate the performance of a newly developed blood pressure (BP) measurement method under different measurement conditions. This study aims to evaluate the performance of using deep learning based method to measure BPs and BP change under non-resting conditions. Materials and Methods: 40 healthy subjects were studied. Systolic and diastolic BPs (SBPs and DBPs) were measured under four conditions using deep learning and manual auscultatory method. The agreement between BPs determined by the two methods were analysed under different conditions. The performance of using deep learning based method to measure BP changes was finally evaluated. Results: There were no significant BPs differences between two methods under all measurement conditions (all P > 0.1). SBP and DBP measured by deep learning method changed significantly in comparison with the resting condition: decreased by 2.3 and 4.2 mmHg with deeper breathing (both P < 0.05), increased by 3.6 and 6.4 mmHg with talking, and increased by 5.9 and 5.8 mmHg with arm movement (all P < 0.05). There were no significant differences in BP changes measured by two methods (all P > 0.4, except for SBP change with deeper breathing). Conclusion: This study demonstrated that the deep learning method could achieve accurate BP measurement under both resting and non-resting conditions. • Key Messages: • Accurate and reliable blood pressure measurement is clinically important. We evaluated the performance of our developed deep learning based blood pressure measurement method under resting and non-resting measurement conditions. • The deep learning based method could achieve accurate BP measurement under both resting and non-resting measurement conditions.
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Blood pressure (BP) measurement accuracy depends on consistent changes in Korotkoff sounds (KorS) for manual measurement and oscillometric pulses for automated measurement, yet little is known about the direct effect of respiration on these physiological signals. The aim of this research was to quantitatively assess the modulation effect of respiration on Korotkoff sounds and oscillometric pulses. Systolic and diastolic blood pressures were measured manually from 30 healthy subjects (age 41 ± 12 years). Three static cuff pressure conditions were studied for two respiratory rates. Cuff pressure [with oscillometric pulses (OscP)], ECG, chest motion respiration [respiration signal (Resp), from magnetometer] and Korotkoff sounds (KorS, from digital stethoscope) were recorded twice for 20 s. The physiological data were evenly resampled. Respiratory frequency was calculated from Resp (fR), OscP (fO) and KorS (fK) from peak spectral frequency. There was no statistically significant difference between fR and fO or fK. Respiratory modulation was observed in all subjects. OscP amplitude modulation changed significantly between the two respiratory rates (p < 0.05) and between the three cuff pressures (p < 0.0001), and decreased significantly with decreasing cuff pressure (p < 0.05). The phase shift between Resp and modulation of OscP was statistically significant with respiratory rates (p < 0.05), but not with cuff pressures. It is accepted that BP in individuals is variable and that this relates to respiration; we now show that this respiration modulates oscillometric pulse and Korotkoff sound amplitudes from which BP is measured.
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Hypertension is the most common condition seen in primary care and leads to myocardial infarction, stroke, renal failure, and death if not detected early and treated appropriately. Patients want to be assured that blood pressure (BP) treatment will reduce their disease burden, while clinicians want guidance on hypertension management using the best scientific evidence. This report takes a rigorous, evidence-based approach to recommend treatment thresholds, goals, and medications in the management of hypertension in adults. Evidence was drawn from randomized controlled trials, which represent the gold standard for determining efficacy and effectiveness. Evidence quality and recommendations were graded based on their effect on important outcomes. There is strong evidence to support treating hypertensive persons aged 60 years or older to a BP goal of less than 150/90 mm Hg and hypertensive persons 30 through 59 years of age to a diastolic goal of less than 90 mm Hg; however, there is insufficient evidence in hypertensive persons younger than 60 years for a systolic goal, or in those younger than 30 years for a diastolic goal, so the panel recommends a BP of less than 140/90 mm Hg for those groups based on expert opinion. The same thresholds and goals are recommended for hypertensive adults with diabetes or nondiabetic chronic kidney disease (CKD) as for the general hypertensive population younger than 60 years. There is moderate evidence to support initiating drug treatment with an angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, calcium channel blocker, or thiazide-type diuretic in the nonblack hypertensive population, including those with diabetes. In the black hypertensive population, including those with diabetes, a calcium channel blocker or thiazide-type diuretic is recommended as initial therapy. There is moderate evidence to support initial or add-on antihypertensive therapy with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in persons with CKD to improve kidney outcomes. Although this guideline provides evidence-based recommendations for the management of high BP and should meet the clinical needs of most patients, these recommendations are not a substitute for clinical judgment, and decisions about care must carefully consider and incorporate the clinical characteristics and circumstances of each individual patient.
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Recent studies have reported differential physiological and psychological effects produced by exclusive right and left nostril breathing and clinical research is required to prove immediate and sustained efficacy of these techniques in various psychosomatic conditions such as hypertension (HT). The present study was designed to determine immediate effects of 27 rounds of exclusive left nostril breathing, a yogic pranayama technique known as chandra nadi pranayama (CNP) on cardiovascular parameters in patients of essential HT. Twenty two patients of essential HT under regular standard medical management were individually taught to perform CNP by a qualified yoga instructor with a regularity of 6 breaths/min throughout a performance of 27 rounds of CNP. Pre and post intervention heart rate (HR) and blood pressure (BP) measurements were recorded using non-invasive semi-automatic BP monitor and Students t test for paired data used to determine significant differences. Twenty seven rounds of CNP produced an immediate decrease in all the measured cardiovascular parameters with the decrease in HR, systolic pressure (SP), pulse pressure, rate-pressure product and double product being statistically significant. Further, gender-based sub-analysis of our data revealed that our male participants evidenced significant reductions in HR and SP with an insignificant decrease in diastolic pressure, while in female participants only HR decreased significantly with an insignificant decrease in SP. It is concluded that CNP is effective in reducing HR and SP in hypertensive patients on regular standard medical management. To the best of our knowledge, there are no previously published reports on immediate effects of left UFNB in patients of HT and ours is the first to report on this beneficial clinical effect. This may be due to a normalization of autonomic cardiovascular rhythms with increased vagal modulation and/or decreased sympathetic activity along with improvement in baroreflex sensitivity. Further studies are required to enable a deeper understanding of the mechanisms involved as well as determine how long such a BP lowering effect persists. We recommend that this simple and cost effective technique be added to the regular management protocol of HT and utilized when immediate reduction of BP is required in day-to-day as well as clinical situations.
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It is known that slow breathing (<10 breaths min(-1)) reduces blood pressure (BP), but the mechanisms involved in this phenomenon are not completely clear. The aim of this study was to evaluate the acute responses of the muscle sympathetic nerve activity, BP and heart rate (HR), using device-guided slow breathing (breathe with interactive music (BIM)) or calm music. In all, 27 treated mild hypertensives were enrolled. Muscle sympathetic nerve activity, BP and HR were measured for 5 min before the use of the device (n=14) or while subjects listened to calm music (n=13), it was measured again for 15 min while in use and finally, 5 min after the interventions. BIM device reduced respiratory rate from 16+/-3 beats per minute (b.p.m) to 5.5+/-1.8 b.p.m (P<0.05), calm music did not affect this variable. Both interventions reduced systolic (-6 and -4 mm Hg for both) and diastolic BPs (-4 mm Hg and -3 mm Hg, respectively) and did not affect the HR (-1 and -2 b.p.m respectively). Only the BIM device reduced the sympathetic nerve activity of the sample (-8 bursts min(-1)). In conclusion, both device-guided slow breathing and listening to calm music have decreased BP but only the device-guided slow breathing was able to reduce the peripheral sympathetic nerve activity.
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Previous studies reported that a device-guided slow-breathing (DGB) exercise decreases resting blood pressure (BP) in hypertensive patients. This study investigated the effects of daily practice of DGB on (a) 24-h BP and breathing patterns in the natural environment, as well as (b) BP and breathing pattern during clinic rest. Altogether, 40 participants with pre-hypertension or stage 1 hypertension were trained to decrease breathing rate through DGB or to passively attend to breathing (control, CTL) during daily 15-min sessions. The participants practiced their breathing exercise at home for 4 weeks. The DGB (but not the CTL) intervention decreased clinic resting BP, mid-day ambulatory systolic BP (in women only) and resting breathing rate, and increased resting tidal volume. However, 24-h BP level was not changed by DGB or CTL interventions, nor was overnight breathing pattern. These findings are consistent with the conclusion that a short-term, autonomic mechanism mediated the observed changes in resting BP, but provided no evidence that regular DGB affected factors involved in long-term BP regulation. Additional research will be needed to determine whether 24-h BP can be lowered by a more prolonged intervention.
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Most devices for measuring blood pressure are dependent on one common feature, namely, occluding the artery of an extremity (arm, wrist, finger, or leg) with an inflatable cuff to measure blood pressure either oscillometrically, or by detection of Korotkoff sounds. Other techniques, which are not dependent on limb occlusion, such as pulse-waveform analysis, can also be used, but these have little application in clinical practice. The array of techniques available today owe their origins to the conventional technique of auscultatory blood pressure measurement, and these new techniques must indeed be shown to be as accurate as the traditional mercury sphygmomanometer. Since the introduction of sphygmo- manometry, mercury and aneroid sphygmomanometers have been the most popular devices for measuring blood pressures. This article has been adapted from the newly published 4th edition of ABC of Hypertension. The book is available from the BMJ bookshop and at http://www.bmjbooks.com/
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Background: Accurately measuring blood pressure (BP) requires choosing an appropriate BP cuff size. Objectives: This study examined trends in mid-arm circumference (mid-AC) and distribution of BP cuff sizes using 1999-2002, 2003-2006, and 2007-2010 National Health and Nutrition Examination Survey (NHANES) data. Methods: NHANES uses a complex multistage probability sample design to select participants who are representative of the entire civilian, noninstitutionalized US population. The analytic sample consisted of 28 233 participants aged 20 years or older. Mid-AC and BP cuff sizes were analyzed across survey years by sex, age, race/ethnicity, hypertension, and diabetic status. Results: Data from NHANES 2007-2010 show that the mean mid-AC for men was 34.2 cm and for women was 31.9 cm. Men showed a significant trend in mid-AC (from 33.9 cm in 1999-2002 to 34.2 cm in 2007-2010; P<0.05 for trend). In addition, 42.9% of men and 25.3% of women needed a large adult BP cuff and 1.9% of men and 2.8% of women needed thigh cuffs to be appropriately cuffed. Moreover, 52% of hypertensive men, 38% of hypertensive women, 59.1% of diabetic men, and 53.6% of diabetic women required the use of BP cuffs with sizes different from those of standard adult-sized BP cuffs for accurate BP measurement. Conclusion: There was an overall significant trend in the mean mid-AC in cm for men but not for women. On the basis of NHANES 2007-2010 data, ∼45% of adult men and ∼28% of adult women required the use of BP cuffs with sizes different from those of standard adult-sized BP cuffs for accurate BP measurement.
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In earlier studies uninostril yoga breathing was shown to influence the activity of the cerebral hemispheres differently, based on (i) auditory evoked potentials recorded from bilateral scalp sites, and (ii) performance in hemisphere-specific tasks. But change in P300 (event-related potential generated when subjects attend to and discriminate between stimuli) from bilateral scalp sites when subjects were practicing uni- and alternate-nostril breathing are yet to be explored. The present study was designed to determine whether or not immediately after uninostril or alternate nostril yoga breathing there would be a change in the ability to pay attention to a given stimulus. Twenty-nine healthy male volunteers, with ages between 20 and 45 years were randomly allocated to five sessions, viz., (i) right-, (ii) left-, (iii) alternate-nostril yoga breathing, (iv) breath awareness and (v) no intervention, each for 45 min on separate days. The P300 event related potential was recorded using an auditory oddball paradigm from sites on the left (C3) and right (C4), referenced to linked earlobes, before and after each session. Post-hoc analysis with Bonferroni adjustment showed that the P300 peak latency was significantly lower at C3 compared to that at C4, following right nostril yoga breathing (P<0.05). These results suggest that right nostril yoga breathing facilitates the activity of contralateral (left) hemisphere, in the performance of the P300 task.
Article
It is accepted that accuracy of auscultatory blood pressure (BP) measurement is influenced by measurement conditions. However, there is little comparative quantitative clinical data. The aim of this study was to provide these data. Auscultatory systolic and diastolic BPs (SBPs and DBPs) were measured in 111 healthy subjects under five different conditions (resting, deeper breathing, talking, head and arm movement). The measurement sequence was randomized, and repeated three times. BPs and their within-subject variabilities were compared with resting values. SBP and DBP changed significantly in comparison with the resting condition: decreasing by 4.4 and 4.8 mm Hg, respectively, with deeper breathing (both P<0.001), increasing by 3.7 and 5.0 mm Hg with opposite arm movement, and increasing by 5.3 and 6.2 mm Hg with talking (all P<0.001). The mean differences between deeper breathing and talking were 9.7 and 11.0 mm Hg for SBP and DBP. The within-subject variability for repeat measurement of SBP and DBP under resting condition were 3.7 and 3.2 mm Hg and increased for non-resting conditions (all P<0.05, except for DBP while talking). We have shown that measurement conditions significantly influence manual auscultatory BPs and their measurement variabilities, and we provide quantitative data to allow comparison of the effects.