Natural outdoor environments can improve quality of life, mental health (e.g. stress, anxiety, depression) and physical health (Triguero-Mas et al., 2015). In fact, more greenery appears to be better – with research showing that denser green areas (e.g. trees along the streets, green public footpaths) are typically inhabited by people with better mental health. 

Studies also show that longer time spent living with greenery is particularly powerful for improving mental health. Individuals who moved from less to more green residential areas improved their mental health, and this remained consistent for over three years. This suggests that these participants’ “baseline” level of wellbeing had improved (Alcock, White, Wheeler, Fleming, & Depledge, 2014).

Additional benefits can be reaped by exercising outdoors. A team of psychologists found that the physical health benefits of exercise outdoors were better for mental wellbeing, sleep, and physical health outcomes that exercise indoors or no exercise at all (Pasanen, Tyrväinen, & Korpela, 2014). 

These trends also make sense from an evolutionary perspective. Modern day human beings are the product of millions of years of evolution, the great majority of it spent living within the wild, natural environment fighting for survival, water, food, and shelter (Cantor, 2009; Mantler & Logan, 2015; O’Connell, 2013).

Our brains have evolved to pay attention to natural cues, rather than man-made ones. For example, human beings show attentional preference towards images of animals and human beings (Wang, Tsuchiya, New, Hurlemann, & Adolphs, 2015). Our species also has a preference for images of nature as opposed to the built environment (Mantler & Logan, 2015).

Several functional magnetic resonance imaging (fMRI) studies have demonstrated how scenes of natural environments activate parts of our brains concerned with positive outlook on life, empathy, emotional regulation, and love, whilst images of urban environments trigger areas of our brain concerned with threat and arousal (G.-W. Kim & Jeong, 2014; T.-H. Kim et al., 2010; Mantler & Logan, 2015).