Keywords
cardiac remodeling - left ventricular geometry - combat sports - exercise - physical activity - athlete’s heart - martial arts
Introduction
Physiological and pathological remodeling, depending on the growth, exercise, or
special situations such as pregnancy in the first case, or as a result of
inflammation, ischemia, or various stresses such as biomechanical stress in the
second case, refer to geometric alterations in the heart muscle [1]. Pathological cardiac remodeling is the process of
various negative factors leading to structural, functional changes in the left
ventricle (LV) in response to internal or external cardiovascular damage or as a
result of various pathogenic risk factors, and often anticipates clinical heart
failure (HF) [1].
The cardiovascular system adapts in response to the hemodynamic stress to which the
body is exposed during training. Athletic training leads to LV remodeling and
physiological adaptation of heart morphology and function. A pattern of LV geometry
is highly dependent on the type of sport, gender, age, comorbidities, and other
factors [2]
[3]
[4]. These morphological changes depend especially on
the type of training and are clinically characterised by changes in size and cardiac
shape due to increased load [5].
Distinguishing athletic cardiac remodeling from pathological remodeling, and thus
from cardiomyopathy, is important and a frequent medical question. Cardiac magnetic
resonance imaging (CMR) plays a crucial role in clinical aid as it can help
physicians discriminate a physiological event from a pathological one where
electrocardiogram (ECG) and echocardiography alone leave several uncertainties. CMR
can more accurately assess cardiac structure and function, as well as thoroughly
evaluate the myocardium by detecting crucial changes such as myocardial scarring
and/or diffuse fibrosis [6].
Judo is an intermittent combat sport that requires high levels of intramuscular
strength. Training at a competitive level requires full-body engagement and a wide
range of both tactical and technical skills to compete at an elite level and it can
therefore cause an adaptation of the geometry of the heart over time [7]
[8]. There are
studies indicating a difference in the increase in relative wall thickness (RWT) and
LV cavity size between genders, i. e. smaller RWT was observed, as well as the size
of its cavities in female than in male athletes [9].
However, the number of studies and data on gender-specific changes in LV myocardial
geometry in combat sports athletes is very limited [10].
Elite judokas regularly implement physically and physiologically demanding training
to remain internationally competitive.
Extreme physical exertion requires aerobic and anaerobic energy sources to provide
adequate energy during training and competition [11].
Previous studies have shown that during intense and strenuous training in judokas,
the heart muscle undergoes significant adaptations [12]
[13]. Long-term athletic training is
associated with a series of alterations in cardiac structure, function and
electrical activity that collectively refer to the broadly defined athlete’s heart
[2]
[14].
However, the clinical profile of the athlete’s heart has greatly expanded over the
years following the increased accessibility and monitoring of athletes
systematically using echocardiography.
Although several studies have evaluated cardiac response to regular exercise training
in male athletes, there is limited data on females, who still make up an
ever-growing number of elite athletes worldwide. A previous comprehensive study
carried out on Italian Olympians revealed that none of the athletes showed absolute
RWT greater than the expected upper limits for the general population, and the LV
cavity was found to be enlarged in only 8% of athletes [15].
The purpose of the present investigation is to examine gender differences in
adaptations of cardiac ventricular geometry among elite judo athletes.
Materials and Methods
We conducted a cross-sectional study at the Vojvodina Cardiovascular Disease
Institute (IKVB) in Sremska Kamenica, Serbia, which included a total of 19
respondents divided into two groups. The data was collected by inspecting the
electronic records of the respondents through the IKVBV computer system. Written
informed consent was obtained from each subject and all procedures were performed
and conducted according to the guidelines of the Declaration of Helsinki and
approved by both the Institutional Review Board of the Faculty of Sport and Physical
Education of the University of Novi Sad, Serbia (Ref. n. 46–06–02/2020–1).
Participants
The study included 19 elite judokas divided into 2 subgroups, the first group
consisted of 10 male athletes (mean age: 25.50±3.17 years), and the second group
consisted of 9 female judokas (mean age: 23.56±3.16 years). All judokas included
in this study were members of the national team and participated in national and
international competitions, achieving numerous victories in major competitions
in their sporting careers, such as the Olympic Games, World Championships and
World Cups. The subjects started practicing judo between the ages of six and
eight; the average duration of judo training experience was 16.55±3.16 years,
with a training volume of 20 to 25 hours per week. Judoka spent 1.5–2 hours
training in the weight room two to three times a week. Participants competed for
the senior national team of Serbia in international competitions and scored for
IJF ranking, achieving the minimum of one ranking. The subjects were of various
categories, from 48 kg up to 78 kg. Four of them reached the Olympic standard
(10th, 10th, 16th, and 18th place WRL), while two of them came close to the
Olympic standard and scored 25th. Three of them participated in the Olympics.
All participants underwent a standard 12-lead surface ECG recording at rest,
with a paper speed of 25 mm/s and a gain of 10 mm/mV. A cardiologist interpreted
each ECG to rule out potential abnormalities. The inclusion criteria were: that
the judokas were elite level, had been judoing for at least 10 years
continuously, and had no particular heart abnormalities so as to compromise the
measurement. Measurements were taken in the early morning hours, before intake
of water or food.
Body composition
Demographic, anthropometric, and echocardiographic data were analyzed for all
subjects.
Analysis of anthropometric characteristics included measurement of body height
(H), performed with a Martin anthropometer, with an accuracy of 0.1 cm,
performed in a standing position with heels together and toes apart, with hands
close to the body. The position of the head during H measurements was horizontal
and the values are expressed in centimeters. Body weight (BW) was determined on
a medical scale with an accuracy of 0.1 kg.
Body surface area (BSA) was analyzed according to the appropriate formula: BSA
(m2)=(√ (H (cm)) x BW (kg))/3600
Left ventricular geometry assessment
All subjects underwent two-dimensional transthoracic echocardiography using a
2.5 MHz low-frequency probe on a Vivid 9 ultrasound machine manufactured by
General Electric’s Co. in the echocardiography department of the Cardiology
Clinic of the Institute of Cardiovascular Diseases of Vojvodina.
The examination was performed in the supine position. Measurements, and
calculations of morphological and functional indicators of the LV chamber were
performed according to the standards of the American Association for
Echocardiography and the European Association for Cardiovascular Imaging [16]. For every obtained set of data, three
consecutive cardiac cycles in an uncompressed format were saved in a cine-loop
structure. Subsequently, one researcher, unaware of the patients’ clinical
details, conducted the analysis offline without any blinding. The following
parameters were measured and calculated: LV posterior wall thickness in diastole
(PLWd, mm); Interventricular septal thickness in diastole (IVSd, mm); relative
wall thickness (RWT, mm) was calculated following the formula: RWT=2 x
PLWd/(end-diastolic diameter) LVIDd (males 52,25±5,80 – females 49,06±2,79) LVMI
was calculated using echocardiographic parameters, according to the following
Devereux formula, automatically in the software system:
IMVS=0.8x (1.04 x [(LVIDd+IVSd+PLWd] x 3 – LVIDd x 3)+0.6. LVMI was calculated by
indexing the patient’s body surface area (BSA, m2).
The geometry of the LV is defined according to the RWT and LVMI. ([Fig. 1])
Fig. 1 Left ventricular geometry [16].
-
Normal geometry (type 1 remodeling): RWT<0.42 and LVMI
♂≤115 g/m2 ♀≤95 g/m2.
-
Concentric remodeling (type 2 remodeling): RWT+≥+0.42 and LVMI
♂≤115 g/m2 and ♀≤95 g/m2.
-
Concentric hypertrophy (type 3 remodeling): RWT+≥+0.42 and LVMI
♂>115 g/m2 ♀>95 g/m2.
-
Eccentric hypertrophy (type 4 remodeling): RWT<0.42 and LVMI
♂>115 g/m2 ♀>95 g/m2.
Regarding the normal range of LVM (g), in accordance with the guidelines and
standards’ Recommendations for Cardiac Chamber Quantification by
Echocardiography in Adults: An Update from the American Society of
Echocardiography and the European Association of Cardiovascular Imaging’ are
88–224 g in men and 67–162 g in women [16].
Data analysis
The data obtained were sorted into the Microsoft Office Excel package (version
2019, Microsoft Inc. Italy), while the IBM SPSS (Statistical Package for the
Social Sciences, version 20.0. IBM Corp.20, Armonk, NY) was used for the
statistical analysis. Data processing included descriptive and inferential
statistical methods. Numerical characteristics are presented using means.
Depending on the nature of the data, the comparison of numerical characteristic
values between the two groups was performed using a t-test for independent
samples.
The results are presented in tables and graphs. The level of statistical
significance was set at p<0.05.
Results
The anthropometric characteristics between the two groups of judokas show
significantly higher values in males in terms of BH (181.90±8.17 cm vs.
166.55±7.28 cm), BM (82.11±10.43 kg vs. 63.92±13.87 kg) and BSA (2.02±0.16
m2 vs. 1.70±0.18 m2) compared to females ([Table 1]).
Table 1 Age and anthropometric parameters of judo
athletes.
|
Males (n=10)
|
Females (n=9)
|
p value
|
|
Mean±SD
|
Mean±SD
|
|
Age (years)
|
25.50±3.17
|
23.56±3.16
|
0.199
|
|
BH (cm)
|
181.90±8.17
|
166.55±7.28
|
0.000***
|
|
BM (kg)
|
82.11±10.43
|
63.92±13.87
|
0.005***
|
|
BSA (m2)
|
2.02±0.16
|
1.70±0.18
|
0.001***
|
Legend: n – number of participants; SD – Standard Deviation; BH – body
height; BM – Body mass; BSA – Body surface area; p value – Statistical
significance; *** – p<0.01; *** – p<0.001.
The analysis found statistically significant differences for IVSd (98.4±10.6 mm vs.
82±5.0 mm), PLWd (97.8±8.9 mm vs. 84.7±6.3 mm), LVM (233.44±68.75 g vs.
164.11±16.59 g), and LVMI (105.16±24.89 vs. 84.66±15.06) in male judokas ([Fig. 2]). However, no significant difference in RWT
was observed between male and female athletes ([Fig.
3]) ([Table 2]).
Fig. 2 Male judokas vs female judokas – LVM, LVMI. Legend: LVM – Left
ventricular mass; LVMI – Left ventricular mass index.
Fig. 3 Male judoka vs. female judoka – RWT. Legend: RWT – Relative
wall thickness relative to the wall of the left ventricle.
Table 2 Cardiac geometry parameters of judo
athletes.
|
Parameters
|
Males (n=10)
|
Females (n=9)
|
p value
|
|
Mean±SD
|
Mean±SD
|
|
IVSd (mm)
|
98.4±10.6
|
82±5.0
|
0.002***
|
|
PLWd (mm)
|
97.8±8.9
|
84.7±6.3
|
0.002***
|
|
RWT mm
|
0.35±0.02
|
0.34±0.01
|
0.167
|
|
LVM (g)
|
233.44±68.75
|
164.11±16.59
|
0.009***
|
|
LVMI
|
105.16±24.89
|
84.66±15.06
|
0.044*
|
Legend: n – number of participants; SD – Standard Deviation; IVSd – Thickness
of the interventricular septum in diastole; PLWd – Posterior ventricular
wall thickness in diastole; RWT – Relative wall thickness; LVM – Left
ventricular mass; LVMI – Left ventricular mass index; p value – statistical
significance; *** – p<0.01; * – p<0.05.
Discussion
In our study, significant differences in heart geometry remodeling between male and
female judokas were demonstrated. As expected, significantly greater LV changes were
observed in male compared to female athletes. The literature has already established
that judokas, regardless of gender, have a significantly higher RWT and greater left
ventricular mass than non-athletes of the same gender [17], however the cardiac remodeling is complex and depends on various
factors [18]. The results obtained are in line with
research conducted to date, which indicate that gender is a significant factor that
has an important influence on the change of heart geometry in athletes [19]
[20]. Whyte et al.
[21] conducted a survey of judokas, including 17
male and 14 female athletes, and 11 participants in the control group. The authors
reported significantly higher RWT values in judokas than in the control group. RWT
was also compared between male and female judokas, whereas significantly higher
values were reported in favor of males. The results are related to the results
obtained in our work [21].
A study of a total of 1083 combat sports athletes (males, n=639; females, n=444),
found significantly lower LVM and RWT values in females than in male athletes, which
matches our findings [10]. Furthermore, our data is
inconsistent with previous research from 2021, conducted on a sample of 200 men and
78 women in weightlifting and various martial arts, which showed that female
athletes were significantly more likely to have an eccentric type of hypertrophy
than men who were more likely to have concentric remodeling of the LV [19]. The adaptations involve the entire cardiovascular
system, particularly in athletes, LV root remodeling can also be expected due to the
hemodynamic load caused by intensive training [22].
Although an increase in LV size has been observed in athletes in the past, as we
demonstrated in our study, there is a limited amount of data in the literature on
this type of remodeling [23]. Cardiac muscle
adaptation in athletes involves a change in the entire cardiovascular system. A
study was performed on the diameter of the LV, whereas a 13% increase was observed
in athletes compared to the control group [24]. In a
sample of 2317 athletes, including 1300 males and 1017 females, a significant
increase in aortic root size was found [23].
All these changes in LV geometry occur due to many factors, such as age, race,
gender, and type of sport. Additionally, hormones are also assumed to have a major
influence on cardiac remodeling in athletes, particularly sex hormones such as
testosterone [25].
It is important to differentiate the athlete’s heart and structural heart disease in
youth [26]. The diagnostic doubt arises when the
remodeling adaptations of the athlete’s heart mimic some pathological conditions,
such as hypertrophic and dilated cardiomyopathies [14]. There is currently little evidence regarding cardiac adaptation to
resistance training in women. However, one study suggests that elite and highly
trained female judokas show significant changes in the morphology of the LV [18]. A cross-sectional report revealed that 24 female
weightlifters demonstrated concentric enlargement of the LV [27]. Considering that the athlete is often subjected
to rapid weight loss [28]
[29]
[30] we can also raise a question
whether this rapid and sudden weight loss before a competition can influence the
athlete’s cardiac remodeling? However, there is still no evidence in the literature
on this.
The limitation of this study is the number of participants, future studies on the
topic with a larger sample of athletes should be carried out. However,
echocardiographic measurement depends on the operator, image quality, interobserver
variability etc.
These results are also associated with the findings of Milovancev et al. (2021)
according to which the physiological model of an athlete’s cardiac adaptation is
complex and varies according to the sport, therefore it must be specified for each
sport discipline [31]. It probably depends on
numerous individual parameters such as individual sport type, duration of practice,
weekly training volume, athlete’s weight category and other variables that influence
the physiology of cardiac adaptation. The literature needs further studies to better
clarify these complex aspects.
Conclusion
Comparison of male versus female heart muscle characteristics, as expected, showed
both higher LVM (albeit still in the physiological range) and higher LVMI in males
compared to female athletes. Based on the obtained results, we can define that LVM
is mildly elevated for males and females, while as regards LVMI, results reported
were within the normal range. Physiological cardiac enlargement in elite level
judokas is an event that can likely occur but still needs further study and
clarification. In fact, males do have larger heart muscle than females.
