Download Cardiac autonomic modulation in judo athletes: evaluation by linear

Sport Sci Health
DOI 10.1007/s11332-015-0256-7
ORIGINAL ARTICLE
Cardiac autonomic modulation in judo athletes: evaluation
by linear and non-linear method
Patrı́cia Souza Araújo3 • Wellington Roberto Gomes de Carvalho3 •
Francisco Navarro3 • Bruno Rodrigues2 • Bruno Bavaresco Gambassi1 •
Bianca Trovelo Ramallo1,2,3 • Antônio Carlos Filho1,2,3 • Cristiano Teixeira Mostarda3
Received: 17 November 2015 / Accepted: 24 December 2015
Ó Springer-Verlag Italia 2016
Abstract
Purpose The practice of judo is associated with some heart
conditions. Some authors suggest cardiac morphometric
changes as an increase in diastolic dimension of the left
ventricle, interventricular septum and posterior wall thickness of the left ventricle with an improvement in aerobic and
anaerobic performance. However, few studies have explored
the autonomic modulation by heart rate variability in judo
athletes. The objective of this study was to evaluate the effect
of judo training 6 months on autonomic modulation analysis, time and frequency domains symbolic.
Methods The study included 16 young male, 18–25 years
of age were recruited from university students through
campus ads and divided into two groups: sedentary young
males (S; n = 9) and judo (n = 7).
Results There are no significant differences in age, height,
weight, body mass index and heart rate among sedentary
groups and judo. During the reporting period, sedentary
individuals displayed parameters of the variability of the
lower heart rate in the time domain, as SDNN, RMSSD,
PNN50 and VarRR, compared with the subjects of judo. As
the symbolic analysis it observed greater parasympathetic
modulation (2UV) in judo group, compared with the
sedentary group. However, no changes were observed in the
sympathetic modulation (0V) between the groups.
& Bruno Bavaresco Gambassi
[email protected]
1
Physical Education Department, Ceuma University,
São Luis, MA, Brazil
2
Faculty of Physical Education, University of Campinas,
Campinas, SP, Brazil
3
Physical Education Department, Federal University of
Maranhão, São Luis, MA, Brazil
Conclusions We conclude that the exclusive practice of
judo for 6 months produces autonomic changes, even
without contributing to changes in body composition.
Keywords Heart rate variability autonomic nervous
system Deconditioning cardiovascular Judo athletes
Introduction
In recent years, the estimated growth in martial arts
worldwide has been around 100 million people throughout
the world (John Corcoran, President of the Curriculum
Committee, American Board of Martial Arts Health
Library, University Sydney). People have been practicing
martial arts for many reasons such as improving self confidence, self defense and physical fitness, combat skills,
health and even some medical conditions [1].
Among martial arts, judo has been studied for its large
tactical development and for being a dynamic art martial
with intermittent high intensity promoting increases in
strength, endurance and power [2–4]. Furthermore, the
judo practice can be used to promote therapeutic, educational, and recreational benefits [5].
Additionally, judo can be associated with several cardiac changes. Some authors suggest cardiac morphometric
changes as an increase in left ventricular diastolic dimension, interventricular septum and left ventricle posterior
wall thickness with an improvement in both aerobic and
anaerobic performance. These changes were found in both
men and women and are similar to the adaptations found in
endurance athletes [6]. It has been observed that judo
practice in juvenile men and senior men and woman has
statistically significant improvements in components like
strength and flexibility [7]. A study also found
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improvements in neural plasticity, showing significant gain
in brain gray matter in judo athletes [8]. However, few
studies have explored the autonomic modulation by heart
rate variability in j udo athletes.
The heart rate variability (HRV) has been used to check
the baroreflex balance of sympathetic–parasympathetic
autonomic nervous system (ANS) and as a measure of
vagal activation during physiological and psychological
tests. The heart rate variability describes the variation
between consecutive heart beats and even when the heart
rate is relatively stable, the time between two heartbeats
(RR) can be significant. Furthermore, decrease in HRV has
been an important mark of cardiovascular and overtraining
conditions [9].
Regarding to Judo practice, the heart rate variability has
been used to assess precompetitive stress in high-standard
judo athletes [10, 11], and a lower perception of recovery
[11], association with performance [12]. However, few
studies showed if judo practice in young athletes promote
the heart rate variability changes in basal conditions.
Thus, the aim of the present study was to evaluate the
effect of 6-month judo training in autonomic modulation
by symbolic analysis, time and frequency domains.
(Declaration of Helsinki, 1964; revised in 2008). All subjects gave written informed consent for this study, which
was approved by the Ethic Research Committee of Federal
University of Maranhao (UFMA).
On the first day of protocol, personal data, clinical and
family history of cardiovascular, pulmonary, metabolic,
and renal diseases, as well as the lifestyle of the participants were collected through interviews. Anthropometric
measures were also taken. On the second nonconsecutive
day of the protocol, at the baseline period (15 min), RR
interval was recorded.
Subjects were instructed to avoid strenuous exercises,
caffeine, tobacco smoking, and alcohol ingestion at least
12 h before data collection days. Data were collected in the
2 days of protocol from 8:00 to 12:00 a.m.
Judo training
Judo training group was composed of seven athletes aged
18–24 from judo team from the Federal University of
Maranhão. After 6 months of training judo performed four
times a week, they were all evaluated.
Anthropometric measurements
Methods
Participants
They recruited 16 young male university students through
advertisements placed in Federal University of Maranhão
and split in two groups: young male sedentary (S; n = 9)
and judo athletes (n = 7). Participants were enrolled
according to the following eligibility criteria: sedentary
group: (1) 18–25 years old; (2) sedentary, with no changes
in physical activity over the previous 3 months; (3) nonobese; (4) non-alcoholic; (5) normotensive, and offspring
of normotensive parents; (6) non-diabetic, and offspring of
nondiabetic parents (7) with no history of cardiovascular,
pulmonary, metabolic or kidney diseases; and (8) under no
medication in the previous week of enrollment. Judo group:
(1) 18–25 years old; (2) Judo athletes, not practitioners of
other physical activity over the previous 6 months; (3) nonobese; (4) non-alcoholic; (5) normotensive, and offspring
of normotensive parents; (6) non-diabetic, and offspring of
non-diabetic parents (7) with no history of cardiovascular,
pulmonary, metabolic or kidney diseases; and (8) under no
medication in the previous week.
Study design
The study was conducted in accordance with World
Medical Association International Code of Medical Ethics
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Anthropometric measurements were performed in accordance to the standard procedures [13]. Body weight was
measured in kilograms (kg) using a digital scale
(SecaÒ 803, Hamburg, Germany) with a precision of
100 grams (g). Height was measured in meters and recorded with an accuracy of 0.1 cm with a portable stadiometer
(SecaÒ 213, Hamburg, Germany). The BMI was calculated
using the formula: BMI = body weight (kg)/body height
(m)2.
Heart rate variability
The electrocardiogram signal (ECG) acquisition was collected at, kHz sample rate, for a 10 min period in the
supine position, head elevation of 30°. It was done using a
protocol with three derivations. To assess the HRV, the
temporal series of RR intervals, was registered by the
WincardioMicromed 600 Hz.
Temporal series from the tachogram were related to
each selected segment, and were quantitatively evaluated
considering the values for the HR, total and normalized
(nu) powers of low frequency (LF—0.04–0.15 Hz) and
high frequency (HF—0.15–0.40 Hz) components of HRV.
The sympathovagal index (LF/HF) was calculated based on
the LF and HF normalized. Normalized units (nu) were
obtained by dividing the power of given component by the
total power (from which VLF was subtracted) and multiplied by 100 [14].
Sport Sci Health
In text format tests were analyzed using the program
Kubios HRV 2.0 (Biosignal Analysis and Medical Imaging
Group, Kuopio, Finland) in which the ECG signal was
processed to obtain the variables related to HRV in the time
domain and frequency. In the time domain variables were
chosen VarRR (Variance of RR intervals), SDNN (standard
deviation of RR intervals) and RMSSD (square root of the
mean squared differences between adjacent normal RR
intervals, expressed in ms) and pNN50, the proportion of
NN50 divided by total number of NNs. In Poincaré plot the
variables were SD1 (short variation of RR interval), SD2
(represents HRV in long-term records). The analysis of
HRV in the frequency domain was performed using Fast
Fourier Transform (FFT) in portions of 5 min with interpolation 4 Hz, overlap by 50 %. The bands of interest were
low frequency or LF (0.04–0.15 Hz and this component
refers predominantly sympathetic modulation) and high
frequency or HF (0.15–0.4 Hz, refers to parasympathetic
modulation).
Normalized LF and HF components of R–R variability
were considered, respectively, as markers of cardiac sympathetic and parasympathetic modulation, and the ratio
between them (LF/HF) was considered as an index of the
autonomic modulation of the heart [14]. The results were
expressed in absolute values (HF and LF ms2) and percentage (HFnu and LFnu).
A symbolic analysis was carried out according to the
approach previously described and validated by Porta et al.
[15]. For this method, the same 5 min of iRR selected
recording was used. Then, a coarse graining approach
based on a uniform quantization procedure was used to
transform the iRR series into a sequence of symbols. The
length (L) was kept fixed in all analyses. The full range of
the sequences was uniformly spread over six levels (from 0
to 5), and patterns of length L = 3 were constructed.
Therefore, each subject and each experimental condition
had its own range of iRR intervals. The Shannon entropy of
the distribution of the patterns was calculated to provide a
quantification of the complexity of the pattern distribution.
All possible patterns (i.e., 216) were grouped without any
loss into three families referred to as (1) patterns with no
variation. The sequences are spread on six levels and all
possible patterns are divided into four groups, consisting of
patterns with: (1) no variations (0V, three symbols equal,
associated to sympathetic modulation); (2) one variation
(1V, two symbols equal and one different associated with
sympathetic and parasympathetic modulation); (3) two like
variations (2LV and associated with parasympathetic
modulation); and (4) two unlike variations (2UV and
associated with parasympathetic modulation) [16].
Table 1 Characteristics of the investigated subjects
Variables
Sedentary (n = 9)
M ± SD
Judo (n = 7)
M ± SD
P
Age (years)
22.5 ± 3.0
19.6 ± 1.3
NS
Height (cm)
175 ± 2
176 ± 0.07
NS
Weight (Kg)
74.7 ± 4
73.6 ± 14
NS
BMI (Kg/m2)
24.3 ± 1
23.5 ± 3
NS
M Mean, SD standard deviation, BMI body mass index
Statistical analysis
For data normality analysis, Shapiro–Wilk’s test was conducted; then, a paired t test for parametric data and the
Wilcoxon Signed Rank Test for nonparametric data were
done. All analyses were conducted using SigmaPlot 12.0
software. Data are presented as the mean ± SD and the
P \ 0.05 was considered statistically significant.
Results
Baseline characteristics
The Table 1 shows the baseline characteristics of sedentary and judo groups. No significant differences in age,
height, weight, body mass index, and heart rate between
the sedentary and judo groups. Heart rate variability in
time and frequency domains can be observed in Table 2.
During the baseline period, sedentary subjects displayed
lower HRV parameters in the time domain, as SDNN
(P = 0.045), RMSSD (P = 0.032), PNN50 (P = 0.015)
and VarRR (P = 0.046), when compared with the judo
subjects. Furthermore, nonlinear method evaluation by
Poincare plot showed reduced values in SD1 and SD2
index in Sedentary than Judo group (Figs. 1, 2). Similarly,
the frequency domain indexes showed that sedentary
individuals demonstrated (in the baseline evaluation) a
lower in LF and HF absolute values than judo group. The
sympathovagal balance, normalized LF and HF component of HRV were similar between sedentary and judo
groups.
The symbolic analysis was expressed in Table 2 and
show greater parasympathetic modulation (2UV) in judo
group when compared to sedentary group. However, no
changes were observed in sympathetic modulation (0V)
between the groups. Similarly, the 1V and 2LV were not
different between them.
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Table 2 Results of heart rate variability in time and frequency
domains
Sedentary (n = 9)
M ± SD
Judo (n = 7)
M ± SD
P
Time domain
RR (ms)
SDNN (ms)
SD1 (ms)
825 ± 83
942 ± 143
0.080
60 ± 8
30 ± 10
90 ± 20
68 ± 23
0.008*
0.003*
SD2 (ms)
74 ± 11
103 ± 36
0.082
RMSSD (ms)
46 ± 13
93 ± 32
0.007*
PNN50 (%)
17 ± 12
40 ± 17
0.015*
3553 ± 900
7806 ± 3124
0.010*
LF (ms )
851 ± 305
2300 ± 631
0.003*
HF (ms2)
725 ± 311
1641 ± 686
0.003*
56 ± 7
59 ± 12
0.604
Frequency domain
VARR (ms2)
2
LF (nu)
HF (nu)
44 ± 7
41 ± 12
0.604
LF/HF
1.3 ± 0.4
1.7 ± 1.0
0.415
Symbolic analysis
0V %
23 ± 4
19 ± 2
0.433
1V %
51 ± 1
51 ± 1
0.835
2LV %
2UV %
14 ± 2
12 ± 3
11 ± 2
19 ± 2
0.226
0.001*
M Mean, SDNN standard deviation of RR intervals, RR mean of
intervals, SD1 short variation of RR interval, SD2 represents HRV in
long-term records, RMSSD square root of the mean of the squares of
the successive differences between adjacents RRs, pNN50 the proportion of NN50 divided by total number of NNs, LF low frequency,
HF high frequency; Relation LF/HF; 0V % (no variations), 1V %
(one variation), 2LV % (two like variations), 2UV % (two unlike
variations)
* Represents significant difference between the sedentary group and
the group of judo athletes
Discussion
The main findings of the present study were that judo
athletes, not practitioners of other physical activity over the
previous 6 months, developed an improvement of cardiovascular autonomic control when compare to sedentary
group.
Was observed an increase in absolute values in SDNN,
SD1, SD2, RMSSD, PNN50, VARR, absolute LF, HF
power and 2ULV %. These data demonstrate a predominance of parasympathetic modulation in judo athletes. It is
noteworthy that these changes were observed regardless of
individual characteristics such as weight, height, age and
body mass index. From what we know, few studies
demonstrated the benefits of practicing judo in autonomic
modulation at rest, regardless of other activities practiced.
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The Judo practice has been shown to be effective in producing several important physiological adaptations to
health as increase in anaerobic and aerobic power [17]. The
dependence on anaerobic metabolism during competition
can be demonstrated by the higher concentrations of lactate, indicating a high rate of anaerobic glycolysis observed
after judo training [17]. However, the aerobic component is
important in cases where the competition continues for
5 min or more (golden score) and there are sequences of
gaming into a single day of competition [7].
Have demonstrated that Judo athletes showed a low to
moderate aerobic power capacity, with VO2max values
higher than those reported in untrained populations [18].
Others benefits promoted by the practice of Judo are cardiac morphometric changes as an increase in left ventricular diastolic dimension, interventricular septum thickness,
posterior wall of the left ventricle with an improvement in
both aerobic as anaerobic performance [6].
In case of autonomic adaptations, several studies shown
that elite athletes have increase in HR variability compared
to sedentary individuals, with a higher relative vagal
modulation and lower relative sympathetic modulation.
Recently, it has been suggested that cardiovascular autonomic regulations are an important determinant of training
adaptations and are also responsive to training effects [19,
20]. Heart rate variability (HRV) has been used as an
important marker of cardiac modulation of sympathetic and
vagal components of the autonomic nervous system (ANS)
[15], so monitoring this activity can be useful for tracking
the time course of training adjustments and for setting the
optimal training loads.
In Judo athletes, the increase in vagal modulation and
decrease of sympathetic modulation in resting was associated with higher increase in heart rate during the exercise
training. Moreover, studies showed that higher vagal
modulation has been associated to heart rate recovery.
Those findings suggest higher performance capacity and
condition to stress support. Possibly, the lactate produced
by anaerobic power in judo practice can induce chemoreflexes changes, modifying heart rate response. Additionally, increase in heart rate variability can be influenced by
baroreflex sensitivity. In fact, studies showed that basal
HRV and vagal modulation was associated with increase in
lactate removal. However, in this study there was no control group at baseline for comparison [12].
In this study, the concern was to select judo practitioners
that did not practice another sport and that had similar body
composition to the sedentary control group. Thus, we
conclude that the exclusive practice of judo for 6 months
produces autonomic changes even without contributing to
Sport Sci Health
Fig. 1 Heart rate variability of
RR intervals in a series of beats
selected in sedentary individuals
(SD1). This index is associated
with vagal modulation;
Instantaneous heart rate
variability of RR intervals
between successive heartbeats
in sedentary individuals (SD2).
This index is associated with the
total variance of beats
Fig. 2 Heart rate variability of
RR intervals in a series of beats
selected in Judo athletes (SD1).
This index is associated with
vagal modulation; Instantaneous
heart rate variability of RR
intervals between successive
heart beats in Judo athletes
(SD2). This index is associated
with the total variance of beats
body composition changes. These changes could be
explained in part by the participation of both aerobic and
anaerobic metabolism in the practice of judo.
Tecnológico (CNPq, Bolsa Produtividade em Pesquisa) and from
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).
Acknowledgments The authors thank the generous cooperation of
the volunteers who participated in this study. Bruno Rodrigues had
grants from Conselho Nacional de Desenvolvimento Cientı́fico e
Conflict of interest
of interest.
Compliance with ethical standards
The authors declare that they have no conflict
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Sport Sci Health
Statement of human and animal rights All procedures performed
in studies involving human participants were in accordance with the
ethical Standards of the institutional or national research committee
and with the 1964 Helsinki declaration and its later amendments or
comparable ethical Standards. This article does not contain any
studies with animals performed by any of the authors.
Informed consent Informed consent was obtained from all individual participants included in study.
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