Rev Bras Fisiol Exerc 2022;21(4):255-74
doi: 10.33233/rbfex.v21i4.5161
REVIEW
Effect of whole-body vibration on cardiac function and functionality in
patients with chronic non-communicable disease: A systematic review and
meta-analysis
Efeito da vibração de
corpo inteiro sobre a função cardíaca e a funcionalidade de pacientes com
doença crônica não-transmissível: revisão sistemática e metanálise
Natalia Tarcila
Santos Amorim1, Maria Julia de Siqueira e Torres Nunes2,
Patrícia Érika de Melo Marinho1
1Universidade Federal de Pernambuco,
Recife, PE, Brasil
2Centro Universitário Tabosa de Almeida,
Caruaru, PE, Brasil
Received: April 29, 2022; Accepted:
October 5, 2022.
Correspondence: Patrícia Érika de Melo Marinho: patricia.marinho@ufpe.br
How to cite
Amorim NTS, Nunes MJST, Marinho
PEM. Effect of whole-body vibration on cardiac function and functionality in
patients with chronic non-communicable disease: A systematic review and
meta-analysis. Rev Bras Fisiol Exerc
2022;21(4):255-74 doi: 10.33233/rbfex.v21i4.5161
Abstract
Objective: To investigate evidence of the use of whole-body
vibration training (WBV) on cardiac autonomic function and functionality in
patients with chronic non-communicable diseases related to the cardiovascular,
respiratory and metabolic systems. Methods: The search involved
Medline/PubMed, Lilacs, PEDro and Scopus databases.
Randomized or quasi-randomized controlled trials were eligible for this review
when comparing a group of patients with cardiovascular, respiratory or
metabolic conditions who trained with WBV with a control group without
intervention or other training modalities. Results: A total of 12
studies were included. Subgroup analyzes were performed considering sample size
and age of participants. WBV training improved sympathovagal
balance and reduced systolic blood pressure in patients with obesity and
hypertension. There was a trend towards an increase in the distance covered on
the six-minute walk test (6MWT) in COPD patients and a decrease in heart rate
(HR) in overweight or obese women and hypertension after WBV, but no difference
was found between the groups. No repercussions were observed in kidney
transplant patients. Conclusion: WBV can be an alternative training
modality to improve cardiac autonomic function and systolic blood pressure in
obese and hypertensive patients, with moderate quality of evidence. We
suggested that larger studies be carried out to assess the effect of WBV on
outcomes such as distance covered in the 6MWT, HR, VO2max, diastolic
blood pressure, gait speed and balance.
Keywords: Cardiovascular system; chronic disease; heart rate;
exercise.
Resumo
Objetivo: Investigar evidências do uso do
treinamento de vibração de corpo inteiro (VCI) na função autonômica cardíaca e
na funcionalidade em pacientes com doenças crônicas não transmissíveis
relacionadas aos sistemas cardiovascular, respiratório e metabólico. Métodos:
A busca envolveu as bases de dados Medline/PubMed, Lilacs, PEDro e Scopus. Ensaios
clínicos randomizados ou quasi-randomizados foram
elegíveis para esta revisão ao comparar grupo de pacientes com condições
cardiovasculares, respiratórias ou metabólicas que treinaram com VCI com grupo
controle sem intervenção ou outras modalidades de treinamento. Resultados:
Doze estudos foram incluídos. Foram realizadas análises de subgrupo
considerando o tamanho da amostra e a idade dos participantes. O treinamento
VCI melhorou o equilíbrio simpatovagal e provocou
redução da pressão arterial sistólica em pacientes com obesidade e hipertensão.
Houve tendência ao aumento da distância percorrida no teste de caminhada de
seis minutos (TC6M) em pacientes com DPOC e redução da frequência cardíaca (FC)
em mulheres com sobrepeso ou obesidade e hipertensão após VCI, porém sem
diferença entre os grupos. Não foi observada repercussão em pacientes
transplantados renais. Conclusão: A VCI pode ser uma modalidade de
treinamento alternativa para melhorar a função autonômica cardíaca e a pressão
arterial sistólica de pacientes com obesidade e hipertensão, com moderada
qualidade de evidência. Por outro lado, sugere-se que estudos maiores sejam
realizados para avaliar o efeito da VCI sobre desfechos como distância
percorrida no TC6M, FC, VO2máx, pressão arterial diastólica,
velocidade da marcha e equilíbrio.
Palavras-chave: Sistema cardiovascular; doenças
crônicas; frequência cardíaca; exercício.
The benefits of whole-body vibration (WBV) training on
human performance have been described in the literature since the mid-1960s
[1]. In addition to the effects on muscle strength and power, flexibility,
balance and bone mineral density [2], neural stimulation triggered from spinal
reflexes also seems to promote changes in cardiac autonomic function, being the
object of study in both athletes and in people with renal [3], respiratory [4]
and cardiovascular dysfunctions [5].
The vibration generated by a platform can be
synchronous, alternating or triplane [6]. Oscillatory movements cause rapid and
repetitive eccentric-concentric action in all types, which evokes muscle work
and consequently increases the metabolic rate [7]. Reflex stimulation of the
muscle spindle and alpha motoneurons located in the spinal cord favors the
synchronization of motor units with a consequent increase in muscle contraction
and tissue perfusion [5,7,8].
Frequency, peak-to-peak amplitude, direction and
duration of vibration are factors, which can determine training intensity [9].
The frequency is measured in hertz (Hz) and represents the number of oscillations
per second, while the amplitude, measured in millimeters (mm), reflects the
displacement magnitude of the vibrating platform [10].
Heart rate variability (HRV) is the time variation
between the RR intervals of an electrocardiogram and can be objectively and
non-invasively evaluated, being able to reflect the cardiac autonomic function
state through observing the heart rate [11]. Sympathetic and parasympathetic
nervous system modulations on this parameter reflect the sympathovagal
balance state [12], and low HRV represents lower parasympathetic activity and
is associated with worse cardiovascular function performance. Thus, therapeutic
strategies that positively influence this variable favor cardiovascular health
[13].
Despite the diversity of protocols and application
forms, associated or not with other therapeutic modalities, frequency, exposure
time and populations with variable characteristics, the effects of WBV on the
cardiovascular system are frequently reported in the literature [5,6,14]. These
benefits can be partly explained by the greater sensitivity of the baroreflex,
the increase in angiotensin II levels and the bioavailability of nitric oxide
[6]. In addition, muscle contractions caused by vibration can more efficiently
reduce endothelial dysfunction compared to training with conventional exercises
and thus induce an increase in muscle mass between 10 and 30% [5,14].
However, considering that cardiac autonomic activity
and functionality levels are often altered in the occurrence of
non-communicable chronic conditions related to the cardiac, respiratory,
vascular and metabolic systems, it is necessary to systematically analyze the
effectiveness of WBV training in these populations. Therefore, the aim of this
study was to perform a systematic review of randomized clinical trials to
verify the effects of WBV training programs to promote sustained improvement in
cardiac autonomic function and functionality in patients with chronic
degenerative cardiac, respiratory, metabolic and vascular diseases.
This review followed a previous protocol according to
PRISMA-P and was registered in PROSPERO: CRD42021277220.
Databases and research
Searches were performed in Medline/PubMed, Lilacs, PEDro and Scopus databases. Descriptors in Health Sciences
(DeCS) and in Medical Subject Headings (MeSH) were used. The search strategy was defined through
the use of the Boolean operators “AND” or “OR” to cross the descriptors as
described in Chart I.
Selection criteria
Types of studies
All experimental randomized or quasi-randomized
clinical trial studies, with participants of both genders, without distinction
of age, published in any language, in the period from 1950 to February 28,
2022, which investigated the efficacy of whole-body vibration training, of any
modality, on cardiac function, including heart rate variability in patients
with chronic degenerative diseases, excluding those of neurological origin,
were included. Observational studies, narrative review or pre-print studies, or
studies that did not describe the WBV training protocol were excluded.
Participants
Studies with participants of both genders, with
chronic degenerative heart, respiratory, vascular or metabolic diseases, without
distinction of age, published until 2022, who had undergone a WBV intervention
protocol.
Intervention
Studies which performed WBV training comparing it with
other physical training modalities and/or with a control group were included.
Studies that evaluated the acute effects of exposure to WBV and that did not
present a control group were excluded.
Outcome
The main outcomes considered were sympathovagal
balance, expressed by the low frequency/high frequency ratio (LF/HF) and the
distance covered in the six-minute walk test (6MWT).
The secondary cardiac outcomes considered were
systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR),
maximal oxygen consumption (VO2max), as well as the frequency domain
of HRV, considering the high-frequency components (HF) ranging from 0.15 to
0.40 Hz and low frequency (LF) ranging from 0.04 to 0.15 Hz. Normalized HF and
LF (nHF and nLF) are
defined as HF or LF/(HF+LF), expressing spectral power as the relative
contribution (percentage) of sympathetic (nLF) and
parasympathetic (nHF) activities in the sinoatrial
node. The analysis of cardiac autonomic function was divided into
improvement/worsening of sympathovagal balance and
increase/decrease in sympathetic or parasympathetic activity. The secondary
functionality outcomes were gait speed and balance.
Data extraction and analysis
Studies were initially selected through title and
abstract analysis by two independent reviewers (NTSA and MJSTN). Then, in a
second more detailed analysis, the reviewers read the full text of the articles
to verify if they met the inclusion criteria of the systematic review. In case
of disagreement between the reviewers on any aspect, a third reviewer (PEMM)
was asked for their analysis. A separate form was used to independently extract
the data.
Evaluation of evidence quality
Evidence quality assessment was performed using the
GRADE [15] system. The outcomes “sympathovagal
balance”, “distance covered in the six-minute walk test”, “heart rate” and
“systolic blood pressure” were used in the evaluation. Five factors can
decrease the quality of evidence in randomized trials: study limitation,
inconsistency, indirect evidence, indirection, imprecision, and publication
bias, according to the classification of evidence level as high, moderate, low,
and very low. The reviewers scored the evidence analysis for each variable
according to the following classification: none (no point reduction), serious
(one-point reduction) and very serious (two-point reduction).
Risk of bias evaluation
The analysis of risk of bias criteria used in Cochrane
clinical trials was used, which considers the risk from the assessment of items
such as randomization, allocation secrecy, blinding, loss control, selective
description of outcomes and early interruption of the study. According to the
guidelines established to assess the risk of bias, they are divided into: high,
low or unclear. Table II presents the evidence quality regarding the outcomes
included in the meta-analysis: sympathovagal balance,
distance covered in the six-minute walk test, systolic blood pressure and heart
rate.
Data analysis strategy
Data were analyzed using Review Manager (RevMan) version 5.30 software program. Ultra-homogeneity of
the studies was evaluated using the heterogeneity test, being considered
homogeneous when p-values were > 0.05. The heterogeneity of the studies was
classified as low heterogeneity when the heterogeneity index (I2) was up to
30%, moderate from 30 to 60%, and high when > 60%. A fixed-effect
meta-analysis was performed in the first statistical analysis. A random effects
meta-analysis was performed when I2 > 60%. The difference of means was used
for studies that used the same assessment instruments, while the difference of
standardized means was used for different instruments. Data available in graphs
were extracted using the web plot digitizer v 4.5 extension program.
Considering the heterogeneity level observed in the studies included in this
review in terms of sample size and age of participants, a subgroup analysis was
performed for the “sympathovagal balance”, “heart
rate” and “systolic blood pressure” outcomes from the number of study
participants (< 5 patients and > 5 patients) and age (< 50 years and
> 50 years).
A total of 121 relevant titles and abstracts were
found in the initial search and 3 studies were found from a secondary search,
totaling 124 studies. Of these, 20 were excluded because they were duplicates
and 33 were excluded after screening the title and abstract reading, as they
did not address the outcomes of interest in this study. Thus, 71 studies were
selected for the next stage, in which 12 studies were included after careful
reading, as they met the inclusion criteria. The flowchart according to the
Preferred Reporting Items for Review and Meta-Analyses (PRISMA) [16] guidelines
in this review is shown below (Figure 1).
Figure 1 - Preferred Reporting Items for Review and
Meta-Analyses (PRISMA) flow chart illustrating the different phases of study
inclusion
The risk of bias analysis of the studies included in
this review is shown in Figure 2.
Figure 2 - Risk of bias summary according to Cochrane
Collaboration criteria
The final sample consisted of 312 individuals, aged
between 18 and 80 years. Five studies [18,19,20,23,24] included only women, one
[21] only men, and another six recruited individuals of both genders
[3,4,22,25,26,27].
The vibration frequency used in the protocols ranged
from 25 to 40 Hz, the duration of the sessions from 10 to 60 minutes, and the
total training duration ranged from 6 to 12 weeks. Regarding health status,
three studies [18,20,23] evaluated the effects of WBV in overweight or obese
women and pre-hypertension or stage one, two hypertension
[19,24] in overweighted or obese women, five studies [4,21,22,26,27] observed
the effects of WBV in Chronic obstructive pulmonary disease (COPD) patients,
and one in kidney transplant patients [3]. Three studies [4,19,22] were
randomized clinical trials with a crossover design. One study [3] was not
included in the meta-analysis of the “sympathovagal
balance”, “heart rate” or “systolic blood pressure” outcomes, as it presented
its results only in median, differing from the presentation of the results of
the other included studies, which presented mean and standard deviation.
Although the lead author was contacted by e-mail, she responded that she did
not have the data of interest for this review. Table I presents the main
characteristics of the studies included in this review.
Sympathovagal balance
Three studies [18,19,24] observed improvement in sympathovagal balance after training with WBV in a
population of young or postmenopausal, overweight or obese, pre-hypertensive or
stage one hypertension women, when compared to no intervention in analyzes by
sample size (Figure 3) and by age (Figure 4), based on moderate evidence
quality (Table II). One study [3] showed no improvement in sympathovagal
balance in kidney transplant patients comparing WBV with Sham.
Distance covered in the 6MWT
Five studies [4,21,22,26,27] evaluated the distance
covered in the 6-minute walk test. In all, the sample consisted of subjects
with COPD, varying the severity level between mild [26], moderate [22,26,27]
and severe [4,21,26]. There was no statistically significant difference in the
distance covered for the WBV intervention groups compared to no intervention
[4,21,26] and calisthenics training [26] in the control groups (Figure 5).
Heart rate
Eight studies [3,18,19,20,22,23,24,25] evaluated the effects of
WBV on HR, with the total duration of the intervention varying between 6 weeks
[19,20,22,24,25], 8 weeks [18] and 12 weeks [3,23]. Six studies
[18,19,20,22,23,25] were included in the meta-analysis because they presented
similar results (Figure 3). There was no reduction in heart rate in overweight
or obese women and in COPD patients after WBV training, with moderate evidence
quality (Table II).
Systolic blood pressure
The results of five studies [18,19,20,22,23,25 showed a
reduction in SBP values after training with WBV in young or postmenopausal,
overweight or obese, pre-hypertensive or stage 1 hypertension women (Figure 3),
presenting moderate evidence quality (Table II). One study [3] did not observe
a difference in the SBP of kidney transplant patients after WBV training.
Diastolic blood pressure
A reduction in DBP values was observed in three
studies; the measurement was obtained by brachial measurement in two studies
[18,20], and one study [25] reported a reduction only in the aortic DBP
measurement in the intervention group, with no difference in the brachial DBP
measurement. Two other studies [3,19] evaluated this outcome, but did not
report any difference in relation to the control group.
Figure 3 - (a) sympathovagal
balance; (b) heart rate; (c) systolic blood pressure from whole-body vibration
versus no intervention in subgroup analysis by sample size.
Figure 4 - (a) sympathovagal
balance; (b) heart rate; (c) whole-body vibration systolic blood pressure
versus no intervention in age subgroup analysis.
Figure 5 - Whole-body vibration versus no intervention and
calisthenics on walking distance
Maximum oxygen consumption (VO2max)
Two studies [3,27] evaluated the maximum capacity for
uptake and utilization of oxygen expressed by VO2max. Only one study
[27] observed an improvement in the values of this outcome in a population of
patients with severe COPD when compared to baseline.
Sympathetic tone (LF)
A decrease in sympathetic tone was observed in three
studies [18,19,24] after intervention with WBV in overweight or obese patients,
whether or not associated with prehypertension and stage 1 hypertension. One
study [3] reported an increase in delta sympathetic tone in the Sham group in
kidney transplant patients.
Parasympathetic tone (HF)
One study [24] found an increase in parasympathetic
tone in the intervention group when compared to the control group, while
another study [18] found an increase in nHF values in
relation to baseline values in the intervention group, but with no difference
in relation to the control group. Two other studies [3,19] evaluated the
parasympathetic tone after WBV, but no difference was observed between the
groups.
Gait speed
A study by Furness et al. [22] observed an
increase in gait speed in COPD patients undergoing WBV training. Another study
[4] which evaluated this outcome found no difference between the groups.
Balance
Only one study [26] evaluated the effect of WBV on the
balance of patients with stable COPD stage I to III according to the GOLD [28]
classification compared to calisthenics. The authors did not observe
significant differences between the groups for the unipedal stance test. Only
the intervention group showed an increase of 1.5 points (0.00 - 4.00 points) in
the multidimensional evaluation carried out using the Berg balance scale.
The results of this systematic review show that WBV
training improved sympathovagal balance in overweight
or obese women [18,19,24], as well as prehypertensive or those with stage one
hypertension [18], however, it did not improve this outcome in kidney
transplant patients for at least one year [3], in which the highest HRV
response occurred in the Sham group. One study [24] showed a positive
correlation between the improvement in sympathovagal
balance and loss of body fat, indicating that a reduction in fat percentage can
contribute to improve the autonomic function of obese women. Other authors
[30,31,32] corroborate this finding, pointing out that endurance training improved
sympathovagal balance, as well as the LF and HF
parameters of HRV, with a reduction in sympathetic tone and an increase in
parasympathetic tone in a population of healthy and obese people in a similar
form to the result obtained with WBV [18,19,24].
Although WBV training did not promote an increase in
the distance covered in the 6MWT in patients with COPD, there is a tendency for
an increase in the intervention group in all studies [4,21,22,26,27] that
evaluated this outcome, considering that the 35-meter increase in the distance
covered in the 6MWT for COPD patients represents the smallest clinically
relevant difference [29]. In addition, two studies [4,22] included in this
review had a crossover design, with the same population exposed to training
with whole-body vibration, with a variation in the washout period from two [4]
to 12 weeks [22]. Studies [33,34] that performed a pulmonary rehabilitation
program twice a week for 8 weeks with aerobic and resistance exercises in the
same population also observed an increase of more than 35 meters in the
distance covered in the 6MWT.
The results included in this review showed a trend
towards a reduction in resting HR after completion of WBV training protocols in
obese women [19,24,25] and in patients with moderate COPD [2]. These studies
also showed that WBV was effective in reducing SBP values [18,19,20,23,25] in the
trained group. Bradycardia and exercise-induced hypotension are chronic desired
effects, widely reported in the literature and often not only associated with
improved cardiovascular health in healthy individuals, but also in patients
with chronic cardiovascular and metabolic conditions, reflecting increased
parasympathetic autonomic control and baroreceptor reflex sensitivity
[30,31,32,35,36,37].
Only two studies investigated the effect of WBV on VO2max
in patients with COPD [27] and in kidney transplant recipients [3]. COPD
patients exposed to WBV increased VO2max compared to baseline, however
with no difference in the control group. One study [38] evaluated the
cardiopulmonary response of patients with severe COPD during WBV training and
observed an increase in oxygen consumption rates after the third minute;
however, so far it cannot be said that WBV training promotes a sustained
increase in VO2max values in this population. The increase in VO2max
as a chronic effect of physical training was described in a study [39] that
investigated the effects of endurance exercises performed with workload above
80% of baseline in a pulmonary rehabilitation program for patients with
moderate and severe COPD. Corroborating these findings, another study [40]
observed that 6 weeks of moderate and high-intensity resistance training in
COPD patients promoted improvement in VO2max values in this
population.
Balance and gait speed were also assessed outcomes and
showed a positive response to WBV training in COPD patients in two studies
[22,26], in contrast to a study [4] in which no improvement in gait speed was
observed after training.
The present review took into account the variation in
sample size and the low number of studies that investigated these outcomes in
patients with non-transmissible cardiovascular, respiratory or chronic
metabolic conditions exposed to WBV, and this limits the understanding of the
training effect on these outcomes, with it being necessary that other studies
are developed to establish the evidence of WBV on the outcomes investigated
herein.
WBV proved to be an alternative training modality for
patients with obesity, hypertension and COPD, who may have low tolerance to
other therapeutic exercise modalities. WBV promoted an improvement in cardiac
autonomic activity expressed by greater sympathovagal
balance, in addition to being effective in reducing SBP baseline values in
patients with chronic non-communicable diseases. There was also a trend towards
a reduction in resting HR and greater distance covered in the 6MWT after
training with WBV, however, given the heterogeneity present in the studies
included in this meta-analysis, we suggest that these outcomes should be
evaluated in larger studies with greater methodological rigor.
Potential conflict of interest
No conflicts of interests have been reported for this
article.
Funding source
Fundação
de Amparo à Ciência e Tecnologia do Estado de Pernambuco (APQ-0182- 4.08/20)
Authors’ contributions
Research conception and design: Amorim NTS, Marinho PEM; Data collection:
Amorim NTS, Nunes MJST; Data analysis and interpretation: Amorim NTS,
Nunes MJST; Manuscript writing: Amorim NTS; Critical review of the
manuscript for important intellectual content: Marinho
PEM