Contact to Nature Benefits Health: Mixed Effectiveness of Different Mechanisms

Abstract

How can urban nature contribute to the reduction of chronic stress? We twice measured the concentration of the “stress hormone” cortisol in the hair of 85 volunteer gardeners (six months apart), relating cortisol level change to (self-reported) characteristics of their recreational activities. Both time spent in nature and physical activity led to decreases in cortisol, while time spent being idle led to an increase. At high levels of present stressors, however, the relationship for time spent in nature and for idleness was reversed. Time spent with social interaction had no effect on cortisol levels. Our results indicate that physical activity is an effective means of mitigating the negative effects of chronic stress. The results regarding the time spent in nature and time spent being idle are less conclusive, suggesting the need for more research. We conclude that if chronic stress cannot be abolished by eradicating its sources, public health may take to measures to reduce it—providing urban nature being one effective possibility.

Psycho-Physiological Stress Recovery in Outdoor Nature-Based Interventions: A Systematic Review of the Past Eight Years of Research

“…The most common activity was walking and/or sitting (22). A few studies involved other activities such as gardening [30,37,54] and relaxation exercises in nature [53,54,59,60]. The durations of the interventions differed substantially and were spread between 15 and 55 min (14), one to several hours (3), one to several days (8), one to several weeks (3), and months (8) (Table 2).…”

“…Three of the studies were CCTs. Two pre-post studies without control groups found no significant decrease from before to after the intervention [53,54]. There was an effect of condition (nature ˃ control) in the CCT study that included a stress recovery measure [46].…”

“…Two CCT studies found positive significant differences in both the intervention and control [34,41]. Two studies—one CCT and one pre-post—found no significant difference in the pre-post measures [39,54]. Of the three studies using anxiety measures, three found a significant decrease from the intervention [29,61,62] and one found a significant difference between intervention and control [44].…”

“…Five studies included measures related to well-being, quality of life, and mental health (Table 4). Four reported significant increases from the intervention [54,56,57,61], with significance levels of p ˂ 0.001–0.000, and one study found no significant effect [54].…”

Scoping review of the impacts of urban agriculture on the determinants of health

“…The positive role of urban gardening in human well-being has also been explored [11]. Additionally, urban gardening has been proven to positively influence stress reduction outcomes [12], foster social cohesion while providing participants the opportunity to build social networks and connect to their community [13].…”