Nature contact and psychological well-being in adults

Abstract

There is growing evidence that contact with natural environments is associated with a multitude of human health benefits including improved mental health and psychological well-being. However, key gaps in the literature persist. Most studies are limited to cross-sectional correlations, and few studies assess in situ autonomic stress responses or control for additive genetic factors. We sought to address these gaps using three separate studies. First, we used longitudinal, ecological momentary assessment methods to investigate affective well-being, and depression, anxiety and stress-related symptoms in employees at Amazon (a multinational e-commerce company), who self-reported on average visitation to a company greenspace and on the naturalness of their day-to-day indoor and outdoor environments. We found that more natural outdoor environments were associated with less anxiety, even after controlling for activity or location types. In another study, we randomly assigned individuals to nature, urban or control sites and used mobile, continuous psychophysiology sensors to track stress responses to an induced stressor, and to the recovery period afterward. We found higher levels parasympathetic and sympathetic activation during the stressor task in the nature and control conditions (compared to urban). We also found a steeper downward slope (i.e., faster recovery) of heart rate in the nature condition. This was the first study to continuously assess in situ responses to both an acute stressor and the recovery afterward within experimental conditions. In the last study, adult twin pairs self-reported on change in behavior (time spent in nature) during COVID-19 and symptoms of depression, anxiety and stress. Data from both monozygotic and dizygotic twins allowed for twin covariances to be decomposed into biometric components (additive genetic, shared environment and unshared environment). Perceived decrease (compared to no perceived change) in time spent in nature was quasi-causally associated with higher anxiety and stress symptom scores. Results also suggested perceived increase in nature contact was quasi-causally associated with higher stress scores. This was the first study to investigate associations between nature contact and mental health outcomes during COVID-19 while controlling for between-family confounds. Collectively, these studies advanced empirical understanding of mental health benefits associated with increased nature contact, and contribute to discourse on public health implications of salutary environmental exposures.