1 in 7 adolescents experience a mental disorder globally, most commonly depression, anxiety and behavioural disorders [1]. Failures to address mental health conditions negatively impact adulthood leading to limited opportunities and lower life satisfaction [1]. Experiences in nature may be a low-cost way to improve the mental health for our young people. Evidence suggests exposure to nature can further help physical ailments.
It is a well known fact that nature has a positive effect on mental health and more recently on physical health. However, are there determining factors which make experiences in nature more effective?
“A prescription for nature” [2]
Research continually provides evidence for the mental and physical health benefits of time spent in nature, including lowering blood pressure, improving cognitive function, and lowering depression [2].
Investigation has begun into the most effective “dose of nature”. The idea behind it is to develop a minimum-dose recommendation similar to that of other health recommendations for physical activity and fruit and veg consumption [3]. Although the idea is simple, public health recommendations like these have inexpensive but substantial outcomes. It has revealed that intensity, frequency, and duration of exposure are all important factors to consider when recommending dose in nature.
Intensity
Quality of nature can be assessed in a variety of ways, including the level of species richness and the number of habitats; the more biodiversity in nature the greater positive impact on health and wellbeing [3]. Another way of measuring intensity of nature is by counting the number of trees in a neighbourhood. Simply increasing the number of trees in a neighbourhood can reduce the prevalence of asthma in children [4].
Frequency
Frequency is measured by the number of times a person is exposed to nature within a specific time frame. This also includes the pattern of exposure, for example is exposure once a week, random, or intermittent? Frequent views of nature during the day can reduce mental fatigue [5].
Duration
Duration refers to the length of time someone is exposed to nature. This can be in regards to long-term exposure (e.g., years lived in a particular landscape) or short-term (e.g., number of minutes spent outside viewing nature) [3].
Although these studies all provide evidence for the benefit of nature on health and wellbeing, there is need for further research. There is yet to be an agreed dosage that is most effective at improving health and wellbeing. Furthermore, results are correlational in nature, and it is not clear as to whether it is the direct experience of nature that improves physical health, or whether it is as a result of the additional physical activity. Either way, the physical and emotional benefits of forest bathing and spending time in nature is worth further investigation.
It is a general conclusion with little specific studies that exposure to nature on a daily basis is associated with better health outcomes [4,5]. With further research, we may find that even less exposure is needed to see effects. Next time you have a lunch break, try going for a short walk and see if you notice any effects on your health and wellbeing.
Incorporating nature into urban environments
What if you don’t have easy access to nature? Studies have found that people that live in the city are at a higher risk of anxiety and mood disorders compared to those living in rural environments [6]. However, urban nature has the potential to address many of the health issues common in those living in cities [7]. Exposure to nature does not have to mean being in an environment consisting mostly of nature (e.g., a forest), but can refer to individual aspects of nature (e.g., a tree or flowers). Incorporating aspects of nature like trees, grass, and vegetation in urban areas can provide greater exposure for individuals.
In conclusion, urbanised areas have exposed people to health risks and reduced time in nature. However, dose modelling used in other areas of health could be used successfully when applied to nature-based health interventions [3]. Scientists, ecologists, and sociologists need to work closely to strengthen evidence for this theory to be accepted by wider fields. Once strong foundations have been built, councils and local governments will be able to increase urban nature and greenspaces to ensure fair access to nature. Not only will this benefit individuals, but it has the potential to reduce healthcare strain by improving health risks associated with living in cities.
References
[1] Adolescent mental health [Internet]. World Health Organization. World Health Organization; [cited 2022Nov11]. Available from: https://www.who.int/news-room/fact-sheets/detail/adolescent-mental-health
[2] Hackenmiller SS. Forest bathing: A prescription for nature. InAPHA's 2019 Annual Meeting and Expo (Nov. 2-Nov. 6) 2019 Nov 4. APHA.
[3] Shanahan DF, Fuller RA, Bush R, Lin BB, Gaston KJ. The health benefits of urban nature: How much do we need? BioScience. 2015;65(5):476–85.
[4] Jiang X, Larsen L, Sullivan W. Connections between daily greenness exposure and health outcomes. International Journal of Environmental Research and Public Health. 2020;17(11):3965.
[5] Hyvönen K, Törnroos K, Salonen K, Korpela K, Feldt T, Kinnunen U. Profiles of nature exposure and outdoor activities associated with occupational well-being among employees. Frontiers in Psychology. 2018;9.
[6] Lovasi GS, Quinn JW, Neckerman KM, Perzanowski MS, Rundle A. Children living in areas with more street trees have lower prevalence of asthma. Journal of Epidemiology & Community Health. 2008;62(7):647–9.
[7] Kaplan R. The nature of the view from home. Environment and Behavior. 2001;33(4):507–42.