One of the priority areas of scientific research in modern sports medicine is the search for highly informative, non-invasive methods to study the impact of stress on heart rate. It is known that stress is a universal adaptive response that causes changes in the functioning of all body control systems. As an adaptive response, stress is often accompanied by a number of negative changes that can become risk factors or even cause functional disorders and diseases. One of the widely applied methods for studying the bioelectrical activity of the heart is the electrocardiogram (ECG), and an important diagnostic parameter that can be determined from the ECG is the heart rate variability (HRV), accounting for the difference between consecutive heartbeats. HRV can be a useful tool to study the influence of stress on the heart rate of the athletes during training.
In the present project proposal, a comprehensive evaluation of the research on the relationship between HRV and the following two types of stress conditions will be carried out:
In order to study the influence of stress on the human body, Holter devices will be used, with the help of which the ECG will be recorded and the RR interval series will be determined, on the basis of which a mathematical analysis will be performed by applying linear and non-linear methods. The linear methods perform the HRV analysis in the time and frequency domains. These methods are standardized and the reference values are known. The nonlinear methods for the analysis and assessment of HRV are potentially promising tools, but they are currently in limited use because they are not standardized and are under active research. According to the recommendations of the European Society of Cardiology and the North American Society of Electrophysiology, the study of the applicability of the linear and the nonlinear mathematical methods for the analysis of HRV are one of the most important priority areas related to cardiac health, which confirms the relevance of this type of research. The nonlinear dynamics methods based on fractal, multifractal, and wavelet theory are increasingly used in the process of information analysis of ECG signals due to the fact that they enable monitoring of heart rate dynamics. These methods complement linear methods that perform analysis in the time and frequency domains.
The application of the mathematical methods for the analysis of HRV will help athletes and their coaches in determining the optimal training loads that will lead to improved sports performance. The monitoring of HRV will also help to detect acute and chronic fatigue, as well as to improve the athlete's physical form and his resistance to stress. In this way, it will be possible to optimize the training of the athletes.
Recent research evidence shows that stressful situations in real life cause an increase in sympathetic activity, part of the autonomic nervous system, and thus increase the heart rate, which leads to a decrease in HRV. The higher the HRV, the better a person's heart adapts to physical (exercise-induced) or emotional (extreme gaming-induced) stress.
The study of the processes taking place in the human body under stress is an actual and significant task that can be solved by applying a new mathematical approach for the analysis and assessment of HRV. The proposed project proposal is relevant and relevant due to the reasons stated above, as well as due to the following two facts:
These circumstances make the current project proposal original and innovative not only due to its scientific nature, but also due to the field of application of the research.
The main goal of the project proposal is to conduct fundamental research by proposing a new mathematical approach for analysing and evaluating the impact of stress on heart rate. Two types of stress will be explored: simulated and real. Simulated stressful situations will be realized through 3D extreme gaming, and real ones will be generated during sports training and fitness. The ECG data obtained under the influence of both types of stress will be analysed and evaluated by applying mathematical methods: linear (in the time and frequency domain) and non-linear methods based on fractal and wavelet theory. Specialized mathematical algorithms will be developed, which will be the basis of applied software to help medical professionals, athletes, coaches, etc.
For the realization of the main objective, the following specific objectives will be fulfilled:
The first specific goal of the project is the modelling of a 3D extreme game and the selection of appropriate techniques for its realization. Algorithmization and creation of the game, by applying two types of systems: without "immersion" and with "immersion". The degree of extremity of the game will be controllable by the user. A comparative analysis of the simulated stress states will be performed by applying the two types of systems (without “immersion” and “immersion”) with respect to the change of HRV. The obtained results will be popularized through scientific publications.
The second specific goal of the project is to conduct a comparative analysis of mathematical methods from the point of view of their informativeness. Representation of the results of HRV research not only by analytical, but also by graphical methods, through which to obtain new theoretical knowledge, scientific results and research approaches to solving the problem of analysis and evaluation of cardiological information obtained in stressful situations. The obtained summarized scientific results will be popularized through scientific publications.
The third specific goal of the project is to investigate the HRV during training as well as during rest of professional athletes or amateur athletes to assess the training load and the recovery process. The results of the analysis can help assess the effects of training, such as cumulative fatigue and determine stress tolerance. The obtained results will be popularized through scientific publications.
The fourth specific goal of the project is statistical processing of the obtained results, by using ROC (Receiver Operating Characteristic) analysis to study the sensitivity and specificity of the parameters of the mathematical methods used. Based on the ROC analysis, the selected methods can be evaluated.
Hypothesis: Carrying out the fundamental research proposed in this project will be a contribution to sports medicine, and it is assumed that through the mathematical methods of analysing cardiac data generated under stress conditions, objective information will be provided to detect acute and chronic fatigue in athletes, as well as and to improve their physical fitness and resistance to stress.
