Effects of urban, natural, and digital environments on physical activity and well-being. Addressing methodological issues in restorative environments research

Background. In recent years, the health benefits of exposure to natural environments have gained increasing attention across multiple fields, including psychology, public health, and urban planning. The growing body of research suggests that interaction with nature can support psychological and physiological well-being. While foundational theories such as the Stress Reduction Theory (SRT) and Attention Restoration Theory (ART) have laid the groundwork for understanding how nature influences psychological health, more recent perspectives, such as the instoration domain, highlight the role of physical activity in nature (green exercise) in enhancing overall well-being. This thesis explores these connections, explicitly focusing on the effects of green exercise on physical and mental health. By integrating psychological, physiological, and environmental factors, the research aims to comprehensively understand nature-based physical activity's restorative potential. Methods. The research comprises three studies designed to investigate the multifaceted effects of nature exposure on health. The first study is a comprehensive review of green exercise research, evaluating the existing methodologies, findings, and potential gaps in the literature. This review also emphasizes methodological challenges such as inconsistent comparison conditions and limited measures of nature exposure, guiding future research directions. The second study is an experimental investigation that assesses green exercise's psychological and physiological benefits. In this study, participants engaged in a one-hour walking session across three environments: urban, natural, and indoor. Physiological markers, including heart rate (HR), heart rate variability (HRV), and cortisol levels, were measured to assess the body’s recovery from stress. Psychological outcomes were evaluated using validated self-report measures of affective states (positive and negative emotions), perceived effort, psychological restoration, and enjoyment of the physical activity. The study examined how these outcomes varied depending on the environment, comparing the restorative and stress-reducing effects of physical activity in nature with those in urban and indoor settings. The third study focuses on hypoxia as a physiological stressor and investigates how exposure to natural environments may support recovery from this stressor. This study explored the impact of hypoxia on both psychological and physiological outcomes, particularly anxiety. It examined whether the restorative qualities of nature (measured through perceived restorativeness) could buffer the psychological impact of oxygen deprivation. Results. The review (Study 1) identified key gaps in the current literature, including inconsistencies in study designs and shortcomings in green space assessment. It highlighted the need for more precise and standardized measures of nature exposure and the integration of individual perceptions of restorative potential in future studies. Results from Study 2 indicated that exposure to natural environments during physical activity significantly improved physiological and psychological health outcomes. Specifically, participants engaging in green exercise showed increased heart rate variability, reduced cortisol levels, and improved mood states compared to those in urban or indoor environments. These findings suggest that nature-based physical activity can enhance stress recovery, improve emotional well-being, and foster positive changes in health-related physiological markers. Results from Study 3 demonstrated that hypoxia induces stress, as evidenced by increased anxiety and changes in physiological markers. However, individual perceptions of restorativeness, especially in natural environments, appeared to buffer the psychological impact of hypoxia. Participants who rated nature-related images as more restorative reported lower levels of anxiety, suggesting that the restorative qualities of nature can mitigate the adverse effects of stressors, even in challenging contexts like hypoxia. Conclusion. Despite mixed findings in the previous literature, this thesis provides robust evidence for the restorative and enhancing effects of nature-based physical activity on psychological and physiological well-being. The findings support the integration of green exercise into public health strategies aimed at improving mental and physical health. Moreover, the results underscore the importance of further investigating the underlying mechanisms of these effects, mainly through the lens of the instoration domain, which emphasizes not only recovery but also the promotion of adaptive behaviors and resilience. These findings contribute to developing interventions and policies that harness the health-promoting potential of natural environments, fostering both individual well-being and broader societal health.