Happy International Day of Forests! Scientific Evidence Shows that Nature Benefits our Health

Exposure to nature has been found to lower levels of stress, improve mood and self-esteem, benefit mental health and cognitive function, and improve cardiovascular healthHappy International Day of Forests! While the International Day of Forests may not be on your list of favourite holidays such as Mother’s day or Valentine’s day, there are many reasons to have a greater appreciation for all forests and outdoor nature in general, in particular, because these environments benefit our health.

When humans are being exposed to nature (e.g. by being in a natural environment or by viewing nature), their body and mind react. Around 75% of the European population [...] lives in cities, where contact with nature is usually scarceExposure to nature has been found to lower levels of stress, improve mood and self-esteem, benefit mental health and cognitive function, and improve cardiovascular health including the heart rate, heart rate variability, and blood pressure. These were the results of experimental studies, in which participants were exposed to nature and their health outcomes were measured during this exposure. These health outcomes were then compared to the health status before being exposed to nature or while being exposed to urban environments.

Photo: Wikimedia Commons

Cities expose us to higher levels of urban stressors such as noise, air pollution and heatIn addition to these short-term effects that we enjoy by visiting or viewing forests or other natural environments, long-term exposure to nature has also been found to positively affect our health. By long-term exposure we mean (almost) daily exposure in your direct living environment such as that surrounding your home or your work place. In general, our daily exposure to nature is decreasing, as today we live further away from nature than ever before. Currently, around 75% of the European population (and over half of the world population) lives in cities, where contact with nature is usually scarce. In contrast, cities expose us to higher levels of urban stressors such as noise, air pollution and heat. Additionally, urban living tends to promote sedentary lifestyles, which are linked to the increasing prevalence of overweight and obesity over the recent decades.

Photo: Fritz Bielmeier

Urban green spaces have been proposed as part of the solution to improving the built environment in cities as they may help protect against urban stressors and a sedentary lifestyle. These green spaces include urban forests, parks, or green corridors, and provide us with our “daily dose of nature” when we visit a park in our neighbourhood, when we see trees looking out of a window, or when we walk or cycle along streets with trees.

Urban green spaces [...] may help protect against urban stressors and a sedentary lifestyleThis regular exposure to nature can benefit your health in several ways. First, green spaces can reduce the level of air pollution and noise in the surroundings. Vegetation improves air quality by taking up pollutants from the air and provides a barrier of noise by absorbing, diverting, and refracting noise. Furthermore, vegetation lowers the surrounding temperature by providing shade and by evaporating water. While this reduction in heat can benefit health directly, there is also an indirect effect: by regulating temperature, the presence of vegetation lowers energy consumption (for heating in winter and for air-conditioning in summer) and thus emissions, which may indirectly affect health.

Second, green spaces can promote physical and social activity; greener neighbourhoods have been reported to foster social cohesion and social support and to increase levels of physical activity. Third, green space may be a resource for psychological restoration. Exposure to nature may evoke positive emotions and reduce stress. In addition, while being exposed to nature, our brain may have a moment to rest, which may restore our ability to direct attention to matters that need more effort to concentrate on.

Photo: Vadim Fomenok

Green space may be a resource for psychological restorationThrough these pathways, long-term exposure to green spaces could improve many health outcomes. Particularly, green spaces have been associated with improved mental health and self-perceived general health, cognitive benefits, reduced levels of obesity, and reduced risk of disease and mortality. These were the results of observational studies that “observed” groups of people from the general population, measuring their health at one point in time (cross-sectional studies) or at several points over a certain amount of time (longitudinal studies). On these measurement occasions, the participants’ exposure to green spaces was assessed by for instance measuring the distance from their home to green spaces or by evaluating the greenness surrounding their home. Subsequently, statistical methods indicated whether those with more exposure to green space had healthier outcomes.

Blue spaces [...] may have similar benefitsSome gaps in research still remain. For instance, we don’t know yet what specific characteristics of green spaces may provide the largest benefits (e.g. the size of the green space or the type of vegetation), nor do we know what frequency and duration of exposure may be optimal. In addition, other types of natural environments such as blue spaces (i.e. water bodies such as rivers, lakes or the sea) may have similar benefits as green spaces. However, the evidence base on the health benefits of green spaces is growing steadily, and we can agree that nature should be appreciated and protected, whether it is a small urban forest or a large natural park. So for now, just take an extra look at that tree outside your window, visit your favourite neighbourhood park, or plan a trip to a natural forest, and enjoy the international day of forests!

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