## 1 Introduction  
By 2050, 16% of the world's population will be aged above 65 years [1]. Although medical technology has enabled individuals to extend their lives, it does not necessarily maintain a favorable quality of life (QOL) [2]. Health-related QOL is the state of one's physical, psychological, and social self-perception over time [3]. Longitudinal studies have indicated that increasing age has a significantly negative effect on QOL [4, 5]. Another cross-sectional study revealed that QOL deteriorates with age [6]. Furthermore, QOL potentially influences older adults' daily living conditions and physical and mental health, whose relationship with age is concerning. Regular physical activity helps improve QOL in older adults and plays an important role in enhancing successful aging [7, 8, 9]. The impact of physical activity on improving the QOL in older adults has been observed in cross-sectional studies, particularly with regard to age-related differences. For example, [PERSON] et al. [6] found the positive correlation between QOL and physical activity to be significantly stronger in old adults than in young-old adults. Similar results have also been found in regular exercise interventions. [PERSON], [PERSON] [10] revealed the effects of multimodal exercises, such as resistance, flexibility, and walking exercises, on QOL in older adults. They observed improvements in both physiological and psychological QOL parameters, such as mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. Furthermore, women aged 75-84 years who had performed balance exercises displayed improvements in their self-perceived physical health [11]. Similarly, health-related QOL in terms of balance impairments in young-old (65-73 years) and middle-old (74-85 years) adults improved over 12 weeks of supervised physical training [12]. Nonetheless, few exercise intervention studies have investigated the QOL of older adults across diverse age groups, and these studies have primarily focused on balance training alone [11; 12] or have exclusively recruited older adults from a single age range [11]. Virtual reality (VR) exercise (e.g., immersive VR, non-immersive VR, interactive VR, etc.) potentially exerts a positive impact on physical and mental health and rehabilitative outcomes compared with traditional exercise [13]. This includes the effectiveness of exergaming-based interventions for mobility and balance performance in older adults with Parkinson's disease [14]; the impact of VR-supported upper-extremity exercise therapy on the motor rehabilitation of motion in sub-healthy people [15]; and the feasibility of, perceptions regarding, and attitude toward the VR-based exercise system in post-treatment patients [16]. It also includes findings on patients' QOL after participating in the intervention. For example, patient participation in VR games or VR-based therapies has a slightly positive impact on QOL [17; 18]. Evidence corroborating the relationship between rehabilitation and QOL across different ages has also been generated [19]. While the current VR-based interventions have mainly targeted sub-healthy populations, two VR exercise interventions have been observed to improve QOL in healthy older adults. First, a previous study found a 6-week short-term VR program to enhance the QOL of healthy older people [20]. Second, [PERSON] [21] explored older adults' participation in 12 weeks of semi-immersive VR fitness training and tracked the effects of discontinuing the intervention. Nevertheless, these studies generally focused on changes in QOL among people aged \(\geq\) 65 years. Engaging in exercise as a strategy to maintain health in older adults' QOL [22; 23]. Studies support the use of concrete physical activity strategies to improve QOL in older adults of various age groups [6]. Considering the prevalence of technological skills in exercise and health, QOL should be prioritized at a later age.