###### Abstract  
This article presents the process of creating a virtual reality (VR) game designed to assess the impact of stress on heart rate variability (HRV). The game features dynamic and challenging scenarios to induce stress responses, incorporating advanced 3D modelling and 3D animation techniques. A study involving 20 volunteers was conducted, with electrocardiographic (ECG) data collected before and during game play. HRV analysis focused on fractal and multifractal characteristics, utilizing detrended fluctuation analysis (DFA) and multifractal detrended fluctuation analysis (MFDFA) methods. DFA results revealed decreased values of \(\alpha_{1}\), \(\alpha_{2}\), and \(\alpha_{\text{all}}\), indicating alterations in short-term and long-term correlations under stress. MFDFA further analyzed changes in fluctuation function Fq(s), generalized Hurst exponent Hq, multifractal scaling exponent \(\tau\)(q), and multifractal spectrum f(\(\alpha\)), showing significant differences in these parameters under stress. These findings validate the game's effectiveness in simulating stress and its impact on HRV. The present study not only demonstrates the relationship between stress and the fractal characteristics of HRV but also offers a new foundation for future applications in psychology, physiology, and the development of VR technologies for stress management. virtual reality (VR); virtual reality game; heart rate variability (HRV); stress; detrended fluctuation analysis (DFA); multifractal detrended fluctuation analysis (MFDFA)  
25 November 202413 January 202513 January 202517 January  
One key aspect that deserves attention is how the VR environment, specifically in 3D games, can affect players' stress levels. Currently, there is no accepted standard for stress assessment [16; 17; 18] as it includes psychological, physiological, and emotional aspects. However, heart rate variability (HRV) is a biomarker that can be used as a method to assess the physiological response to stress. This approach is innovative in assessing autonomic nervous system responses, measuring fluctuations in the intervals between successive heart-beats, and reflecting the balance between the sympathetic and parasympathetic nervous systems [19; 20]. The sympathetic system is associated with the \"fight or flight\" responses activated in stressful situations, while the parasympathetic system controls rest and recovery functions. During stressful situations, sympathetic activity increases, leading to an increase in heart rate and a decrease in HRV. Conversely, during relaxation and recovery, the parasympathetic system dominates, resulting in higher heart rate variability [21; 22]. Therefore, valuable information about the body's psychophysiological responses, including levels of stress and mental strain, can be obtained through the analysis of HRV. Low HRV is often associated with chronic stress, fatigue, and risk of cardiovascular disease, while high HRV is a sign of good health and the body's adaptability to external stressors. This makes HRV a key tool for studying stress under various conditions, including intense situations such as those created by virtual realities and games [23; 24]. Changes in HRV can reflect the impact of various external factors on the body, such as physical and mental exertion, stress and arousal. HRV analysis provides information on cardiac dynamics and nervous system regulation, making it a useful method for investigating stress during VR gaming. It allows researchers to observe in real time the physiological changes induced by these situations, providing valuable information about stress levels and the body's adaptability. The research results in references [25; 26; 27] show that the heart rate increases significantly and HRV decreases when participants are subjected to gaming-induced stress. The study of HRV during VR gaming enables a better understanding of the interplay between emotions, the nervous system, and the gaming experience of gamers.