The control of the cardiovascular system is performed in part by the autonomic nervous system (ANS), which provides afferent and efferent nerves to the heart in the form of sympathetic terminals throughout the myocardium and parasympathetic to the sinus node, the atrial myocardium and the atrioventricular node (18) The influence of SNA on the heart depends on the information of baroreceptors, chemoreceptors, atrial receptors, ventricular receptors, modifications of the respiratory system, the vasomotor system, the renin-angiotensin-aldosterone system and the thermoregulatory system (20, 31).
Este control neuronal está estrechamente relacionado con la frecuencia cardíaca (FC) y la actividad refleja barorreceptora (28). A partir de la información aferente, a través de una interacción compleja de estimulación e inhibición, las respuestas de las vías simpática y parasimpática modifican la FC para adaptarla a las necesidades de cada momento. El aumento de la FC es la consecuencia de la mayor acción de la vía simpática y la menor actividad parasimpática (es decir, la inhibición vagal), mientras que la disminución de la FC depende principalmente del predominio de la actividad vagal (18,28) Read about Enochlophobia Here https://itspsychology.com/enochlophobia/.
The heart is not a metronome and its beats lack the regularity of a clock, so the HR changes defined as the heart rate variability (HRV) are normal. Changes in HR indicate the ability of the heart to respond to multiple physiological and environmental factors, including breathing, physical exercise, mental stress, hemodynamic and metabolic changes, sleep and orthostatic (3,6 ). The regulation of the autonomic nervous system is directly related to the release of catecholamines, which is sensitive to different training stimuli and is presented as an interesting tool in the identification of acute and chronic responses that result from different training stimuli.
The data obtained from the heart rate transcribe the physical and mental state of rest even at the end of the exercises. In this context, the analysis of the heart rate variability, which consists of the oscillations of the intervals between consecutive heartbeats (9), can be an effective tool to understand the relationship between cardiovascular risk factors and the autonomous response. It is known that parasympathetic activity can be suppressed and is closely related to positive stress due to cardiometabolic complications (20,29).
Interestingly, this same activity can be stimulated by the increase in cardiorespiratory fitness and physical training (18). It has been demonstrated that HRV is a useful tool to control individual adaptations to a training program, as well as for the treatment of disorders such as stress and anxiety (9). Psychological factors such as anxiety, mood and self-confidence have a direct relationship with the performance of athletes and their inability to face sports situations, especially during pre-competition in which the psychological reactions that lead to the athlete can occur failure. Therefore, the purpose of this study was to correlate the variability of heart rate and self-confidence status in elite canoeing athletes.
The study consisted of 34 male athletes with an average age of 20.11 ± 4.82 years, the height of 172.41 ± 9.12 cm and body weight of 68.64 ± 10.1 kg. All the subjects presented more than 3 years of high-performance training and international competition results. Subjects were analyzed during the strength training period of the general training plan established by the Brazilian Canoe Confederation (CBC) to have greater control of all sports activities and nutritional status. The subjects were informed about the objectives and procedures of the study and, after the agreement, signed an informed consent form, which was approved by the Ethics Committee of the Faculty of Medical Sciences of the Santa Casa de Sao Paulo (FCMSCSP) with the number 518,993 of 01/29/2014.
This study was transversal, descriptive and correlational. The subjects maintained their training programs during the month prior to the investigation. The evaluation of self-confidence states was performed immediately before the heart rate variability test. The inventory was read item by item by the evaluator so that all subjects could mark their response. The subjects did not consume any dietary or ergogenic supplement before or during the study.
Heart Rate Variability (HRV)
For the analysis of heart rate variability (HRV), the resting heart rate was recorded beat-by-beat using a heart rate monitor (Polar®, model RS800, Kempele, Finland), validated for the purposes of this study for determining the RR intervals (13). While the subjects breathed normally in the supine position for 30 minutes, the tape of the electrode was placed at the level of the xiphoid process of the sternum. The watch to capture the information was fixed on the wrist, which kept the arms extended to the side of the body. All athletes were instructed to abstain from caffeine and physical activity for 24 hours before the test, and the assessments were made in the morning to avoid possible circadian rhythm influences,
The data was recorded in the beat-to-beat mode in milliseconds, which was downloaded by infrared transmission to a laptop from the Polar Pro Trainer software (version 5.41.002). The data filtering method followed two steps: (a) digital filtering through the software used to download the data; and (b) manual filtering to visually verify the variations between heart rate ranges that allowed eliminating abnormal intervals (9,12). A thousand RR intervals were used to analyze the data, which were calculated using the Kubios VFC software, version 2.0, the average RR intervals (M-IRR) and the heart rate variability index using the linear method, and in the time domain: rMSSD
The rMSSD index corresponds to the quadratic mean of the successive square differences between the consecutive RR intervals, in which it represents the predominance of the activity of the parasympathetic autonomic nervous system (18). The SDNN index reflects the participation of both branches of the autonomic nervous system (ANS) and represents the standard deviation of the mean of all normal RR intervals, expressed in milliseconds (3). The VFC undergoes transformations in fundamental oscillatory components in the frequency domain where the low-frequency components are analyzed (BF – 0.04 to 0.15 Hz), which is related to the joint action of the vagal and sympathetic components with predominance of the sympathetic over the heart, and high frequency components (AF – 0.15 to 0.4 Hz). The latter is an indication of the action of the vagus nerve in the heart. In addition, the BF / AF ratio is characterized by sympathetic-vagal equilibrium over the heart.
The spectral analysis is calculated using the Fourier. All measurements were taken with the athletes wearing light clothing and barefoot. The body weight was measured on a digital reading scale (Filizola®, Personal Line 200 model, Brazil) with an accuracy of 0.1 kg. The stature of the subjects was determined by a stadiometer fixed on the wall (Sanny®, professional model, Brazil) with an accuracy of 0.1 cm.
Sports Self-Reliance Inventory
The sports self-confidence inventory (SCI) was used to assess the level of self-confidence of the subjects. The SCI (4,14) is composed of 14 items distributed in three subscales: (a) Self-confidence in Physical Skills and Physical Training (SPST); (b) Self-confidence in Cognitive Efficiency (SCE); and (c) Resilience Self-Reliance (RS). The scale consists of the following classifications:
7. Absolutely true (absolute certainty that yes);
6. Practically correct (almost certainly);
5. Pretty good (I think so);
4. Maybe (I have doubts);
3. Very uncertain (I think not);
2. Practically uncertain (almost certainly not); and
1. I can not do it at all (absolutely not).
The results are presented as mean ± SD. The normality of the data was verified by the Smirnov Kolmogorov Test. For the multivariate model, the rMSSD index was subjected to a logarithmic adjustment (log10). Due to the use of some variables of parametric origin, the Pearson correlation was used to verify the relationship between the self-confidence inventory (SCI) and the heart rate variability (HRV). Statistical significance was established at a P value of less than 5% using SPSS software 17 (SPSS Inc., Chicago, IL).
The descriptive results (mean ± SD) are shown in Table 1, which also includes the minimum and maximum body composition and the levels of metabolic performance that characterize the athletes. Table 2 presents the Variables of the Heart Rate Variability. Table 3 presents the results of the correlation analysis of the variables in the SCI with a variability of the heart rate of which there were significant correlations for the following variables: SPST with rMSSD (r = 0.40, P = 0.018) and SPST with AF (r = 0.39, P = 0.02).
SPST = Self-confidence in Physical Skills and Physical Training; SCE = Self-confidence in Cognitive Efficiency; SR = Self-confidence in Resilience; rMSSD = Quadratic Mean Square Successive Differences; BF = Low frequency components; AF = High frequency components; BF / AF = The Relationship is characterized by the Sympathetic-Vagal Balance over the heart.
The purpose of this study was to verify the possible correlations between an inventory of self-confidence (SCI) and the variability of the heart rate (HRV) of Olympic slalom athletes. The main correlations were observed between self-confidence in physical abilities and physical training (SPST, r = 0.39, P = 0.02) and HRV variables related to the parasympathetic activity. The vagus nerve that acts on the heart seems to help athletes control high levels of anxiety, which increases their expectations of achieving a high level of performance. Similarly, the rMSSD variable that indicates the predominance of parasympathetic autonomic nervous system activity also showed a correlation between self-confidence in physical abilities and physical training (r = 0.40, P = 0.018).
It is known that with the advance of age there is a tendency to decrease the vagal response with a decrease in HRV (12), but this behavior does not seem to be the case among young athletes (18,29,31). Numerous authors (1,15,22-25) have determined values associated with the normality of HRV and suggested reference values of 27 ± 12 ms and from 8 to 24% for rMSSD and pNN50, respectively. In the present study, when the indices obtained were analyzed, the canoeists presented higher values of rMSSD (53.64 ± 20.28 ms) in comparison with the reference values. The highest values are consistent with the high level of conditioning of the athletes that is related to a predominant parasympathetic activity.
It should be noted that physical exercise has a modulating role in cardiorespiratory fitness and, therefore, may delay the reduction of parasympathetic activity (1,5,6,10,19,21,24,27). Physically active persons have a lower HR at rest that suggests greater parasympathetic activity attributed to intrinsic adaptations of the sinus node or also due to other physiological changes such as increased venous return and stroke volume, as well as positive changes in myocardial contractility ( 10,16,17,26).
Workouts characterized by high intensities are extremely important components in improving athletic performance (2,7,8,11). However, the choice of the highest percentage of the type of training is characterized by the specificity that the modality requires or even by the periodization of the training. In this way, physical and physiological adaptations are differentiated according to the type of training chosen (ie, high-intensity training and short-term training) resulting in acute responses such as blood lactate production and hormonal activity. catecholamines and cortisol (32). Conversely, low-intensity, long-duration training tends to increase the mitochondrial content and respiratory capacity of muscle fibers (25,30).
Regarding the different types of training that are associated with myocardial adaptations, low-intensity training promotes an improvement in the contractility of the left ventricle and a small increase in the thickness of the left ventricle. On the contrary, high-intensity training promotes the great muscular development of the left ventricle (25) with values of systolic volume essentially unchanged. In this sense, the quantifications of training loads, as well as the evaluation of the behavior of the autonomous modulation of FC versus the chronic stimulus, are tools that can promote responses with a high degree of validity. Considering the lack of scientific studies on canoeing,
Based on the results observed in the present investigation, it is possible to conclude that the VFC of the athletes presented a vagal predominance before the beginning of the training. Future research involving longer periods of training within a macrocycle is necessary to investigate possible changes in HRV in athletes of this modality. Therefore, it can be concluded that the sports practice of canoeing was related to the indicators of HRV of the parasympathetic domain during rest. The data indicate that the assessment of the self-confidence inventory was efficient in relation to the resting state of the canoeing athletes. The transversal design does not allow establishing a causal relationship between the results presented. Nevertheless,