Benefits of nature contact

There is a well-established body of research demonstrating important links between spending time in nature and mental, physical and social health – general well-being in other words.

Physical health benefits

The physical health benefits of nature contact are the most well-documented and are linked to numerous ‘active’ ingredients including: high air quality (reduced air pollution); specific microorganisms that appear to boost immune function; negative air ions, which may reduce depression (Perez, Alexander, & Bailey, 2013); and, natural sights and sounds, which have important physiological impacts on the nervous system, help to restore attention and promote healing after surgery (Ulrich, 1984). Forested areas are also high in phytoncides, chemicals produced by trees and plants that reduce blood pressure, increase immune function (Li et al., 2006) and relieve depression. 

Here is a summary of positive impacts of nature on physical health (Keniger, Gaston, Irvine, & Fuller, 2013; Kuo, 2015):

- Reduced prevalence of:

• Respiratory disease
• Diabetes mellitus
• Various infectious diseases
• Cardiovascular disease and mortality
• Musculoskeletal complaints
• Infectious intestinal diseases
• Urinary tract infections
• Vertigo

- Faster recovery from surgery

- Increased immune function

- Reduced headaches, including migraines

- Reduced mortality rates for some cancers

- Reduced health risk factors

- Reduced occurrence of illness

- Reduced blood pressure

Even emotional experiences such as regular experiences of awe and a sense of vitality, both of which can be experienced in nature, can predict healthier levels of inflammatory substances (Stellar et al. 2015), and greater resistance to infection and lower risk of mortality (Kuo, 2015).

Exposure to natural settings also affects our perception of our health. One study (Kardan et al., 2015) showed that people who live in neighbourhoods with more street trees reported significantly higher health perception: "having 10 more trees in a city block, on average, improves health perception in ways comparable to an increase in annual personal income of $10,000 and moving to a neighborhood with $10,000 higher median income or being seven years younger."

Mental health benefits

The mental health benefits of nature contact are particularly significant given the poor state of mental health funding and support systems in Australia. This table summarises the benefits to psychological and cognitive mental health (Keniger et al., 2013; Kuo, 2015). What is so remarkable about spending time in nature is that it can simultaneously reduce negative mental health and promote positive mental health, unlike traditional mental health treatments.

Neuroscience is also starting to uncover parts of the story about what happens to our brains in nature. A behaviour associated with heightened risk of depression is rumination, ‘a maladaptive pattern of self-referential thought’ (Bratman, Hamilton, Hahn, Daily, & Gross, 2015, p. 1), which is associated with a part of the brain called the sgPFC. An American study (Bratman et al., 2015) showed that a 90-minute nature walk decreased both self-reported rumination and neural activity in the sgPFC, compared with a 90-minute urban walk, which had no effect. This suggests that time in nature could assist in preventing depression.

A brain imaging study found that only when viewing images of urban areas, as compared to viewing natural scenes, parts of the brain were activated that are associated with negative emotions including anxiety, fear, aversion, anger and unpleasantness (Kim et al., 2010).

In 2016 an Australian study showed that up to “7% of depression cases and 9% of blood pressure cases could be prevented if all city residents were to visit green spaces at least once a week for an average duration of 30 minutes or more” (Shanahan et al., 2016, p. 3).  

Social health benefits

The social benefits of being in nature with other people are well-documented (Keniger et al., 2013), and the social factors of wellbeing are arguably the foundation of wellbeing. Being in nature with others can:

• Facilitate social interaction
• Enable social empowerment
• Reduce crime rates
• Reduce violence
• Enable interracial interaction
• Improve social cohesion
• Provide social support

A study with social and mental health implications for immigrants (Hordyk, Hanley, & Richard, 2015) suggests that activities in natural spaces can help to reduce the effects of migration stress on three social determinants of health for migrants: poor or inadequate housing, lack of social cohesion and psychosocial stress. Families in this study were particularly clear about the importance of a third party in helping them to access nature, including practical help in preparing for unfamiliar seasonal conditions, and active assistance organising daytrips, or providing information. 

References

Bratman, G. N., Hamilton, J. P., Hahn, K. S., Daily, G. C., & Gross, J. J. (2015). Nature experience reduces rumination and subgenual prefrontal cortex activation. Proc Natl Acad Sci U S A, 112(28), 8567-8572. doi:10.1073/pnas.1510459112

Hordyk, S. R., Hanley, J., & Richard, E. (2015). "Nature is there; its free": Urban greenspace and the social determinants of health of immigrant families. Health Place, 34, 74-82. doi:10.1016/j.healthplace.2015.03.016

Kardan, O., Gozdyra, P., Misic, B., Moola, F., Palmer, L. J., Paus, T., & Berman, M. G. (2015). Neighborhood greenspace and health in a large urban centre. Sci. Rep., 5. doi:10.1038/srep11610

Keniger, L. E., Gaston, K. J., Irvine, K. N., & Fuller, R. A. (2013). What are the Benefits of Interacting with Nature? International Journal of Environmental Research and Public Health, 10, 913-935.

Kim, G. W., Jeong, G. W., Kim, T. H., Baek, H. S., Oh, S. K., Kang, H. K., . . . Song, J. K. (2010). Functional neuroanatomy associated with natural and urban scenic views in the human brain: 3.0T functional MR imaging. Korean J Radiol, 11(5), 507-513. doi:10.3348/kjr.2010.11.5.507

Kuo, M. (2015). How might contact with nature promote human health? Promising mechanisms and a possible central pathway. Front Psychol, 6, 1093. doi:10.3389/fpsyg.2015.01093

Li, Q., Nakadai, A., Matsushima, H., Miyazaki, Y., Krensky, A. M., Kawada, T., & Morimoto, K. (2006). Phytoncides (wood essential oils) induce human natural killer cell activity. Immunopharmacol Immunotoxicol, 28(2), 319-333. doi:10.1080/08923970600809439

Perez, V., Alexander, D. D., & Bailey, W. H. (2013). Air ions and mood outcomes: a review and meta-analysis. BMC Psychiatry, 13, 29. doi:10.1186/1471-244X-13-29

Shanahan, D. F., Bush, R., Gaston, K. J., Lin, B. B., Dean, J., Barber, E., & Fuller, R. A. (2016). Health Benefits from Nature Experiences Depend on Dose. Sci Rep, 6, 28551. doi:10.1038/srep28551

Ulrich, R. S. (1984). View through a Window May Influence Recovery from Surgery. Science, 224(4647), 420-421.

Stellar, J.E., John-Henderson, N., Anderson, C.L., Gordon, A.M., McNeil, G.D., and Keltner, D. (2015). Positive affect and markers of inflammation: discrete positive emotions predict lower levels of inflammatory cytokines. Emotion 15, 129–133.