Can getting in the green help beat COVID-19?

Updated 16 November 2020

Of the many confusing, contradictory, nonsensical and even bizarre edicts that have been issued since the world declared war on a coronavirus, one of the most disturbing and irrational was the closure of national parks, urban parks and other green spaces in many countries, including Australia.

Firstly, it make absolutely no sense, given that – as with other viruses that spread through respiratory droplet infection – outdoor transmission of SARS-CoV-2 is exceptionally rare. Even the slightest air current rapidly disperses the viral particles suspended in a respiratory droplet, diluting them to the point where their prospect of infecting another person is extremely slight.

Sunlight also inactivates the virus within minutes (just 2 minutes at the equivalent of summer sunlight, and 4 minutes of winter sunlight).

Not a single outbreak involving 3 or more cases of SARS-Co-2 infection was identified in a study of 318 clusters of infection that occurred in Chinese municipalities outside Hubei. In fact,

“Among our 7,324 identified cases in China with sufficient descriptions, only one outdoor outbreak involving two cases occurred in a village in Shangqiu, Henan. A 27-year-old man had a conversation outdoors with an individual who had returned from Wuhan on 25 January and had the onset of symptoms on 1 February.”

Indoor transmission of SARS-CoV-2

Secondly, lack of exposure to green spaces has serious detrimental effects on mental and physical health, including immune function, and even influences rates of violent crime.

Research on the benefits of exposure to nature has burgeoned over the last few years. Among the fascinating findings that have emerged are the following:

1. Contact with nature enhances immune function

A fascinating review titled ‘How might contact with nature promote human health? Promising mechanisms and a possible central pathway‘ summarises the ways in which contact with nature benefits our immune function:

• Phytoncides emitted by trees and other plants boost the function of our natural killer cells, which play a key role in defending us against viral infections.
• Mycobacterium vaccae, a bacterial species that occurs naturally in soil, regulates immune function and attenuates inflammation – important actions in preventing the ‘friendly fire’ activity of the immune system that can cause serious illness in people infected with SARS-CoV-2.
• Negative ions are abundant in the air in forested and mountainous areas, and near moving water, and have been found to boost immune function in animal studies.
• Environmental biodiversity may benefit immune function via its effects on the gut and skin microbiota.
• Taking a walk in a forest raises the levels of adiponectin, a hormone which boosts natural killer cell activity and reduces inflammatory cytokines (key chemicals in the ‘friendly fire’ immune response), while urban walks do not.
• Contact with nature promotes experiences of awe, which are associated with lower levels of inflammatory cytokines; and enhance vitality, which predicts increased resistance to infection.
• Even the sights and sounds of nature influence immune function, via their effects on the balance between sympathetic nervous system activity (the fear-fight-flight response which, when prolonged, suppresses cellular immunity, the arm of the nervous system which is primarily involved in fighting viral infections) and parasympathetic nervous system activity (the rest-digest-heal response, which acts as a ‘reset’ after an organism has been stressed).
• Greener residential areas are associated with lower rates of obesity, a state that is not only immunosuppressive but also proinflammatory. This anti-obesity effect that does not appear to be mediated by increased physical activity levels. Amazingly, just living in an area that provides ready access to green space appears to promote a healthier body weight through its effects on adiponectin, sleep and impulse control.

No doubt there are many other mechanisms by which time spent in nature improves immune function, that have yet to be discovered and elucidated by scientists.

2. Exposure to nature reduces stress

Compared to equivalent amounts of time spent sitting or walking in urbanised environments, just 10 to 50 minutes of time spent sitting or walking in green spaces such as nature reserves, urban parks, or forests, was found to significantly reduce physiological markers of stress (as measured by decreased heart rate, cortisol levels, blood pressure and sympathetic nervous system activity; and increased parasympathetic nervous system activity and heart rate variability) in young people aged 15-30. The authors of this detailed review noted that the same effects have been observed in older adults.

Psychological measures of stress also improved, as indicated by several validated scales for assessing mood and anxiety levels, as well as significant increases in self-reported feelings of calm, comfort, and being refreshed and restored.

Since, as mentioned in the previous section, prolonged stress suppresses immune function, providing access to green space should be a top priority of all public health officials who wish to serve the best interests of the citizens they’re charged with protecting – especially in the midst of the highly stressful social and economic chaos to which those citizens are currently being subjected.

3. We need to heed the call of the wild

Wild spaces – including features such as old growth trees, large open spaces, expansive vistas, opportunities to observe wildlife, and the experience of solitude and removal from civilisation – appear to offer more benefits to human well-being than tamer natural settings such as parks with manicured lawns and garden beds.

In a provocative paper titled ‘Relatively Wild Urban Parks Can Promote Human Resilience and Flourishing: A Case Study of Discovery Park, Seattle, Washington‘, visitors to the park described their experiences with the relatively wild aspects of the park as far more meaningful, stress-reducing and restorative than the more domesticated aspects.

In the light of this research, the closure of national parks in the midst of the SARS-CoV-2 pandemic was a massive public health policy fail, while the Tasmanian government’s decision to dispatch the Westpac rescue helicopter to locate and fine people camping in remote wilderness areas was next-level ludicrous for its utter lack of scientific merit and flagrant misuse of scarce resources.

4. Wilderness areas promote the satisfaction of human psychological needs, including autonomy, competence and relatedness

Anyone who has taken an entry-level course in human psychology is familiar with the Hierarchy of Needs formulated by Abraham Maslow:

As soon as our basic survival needs are met, we humans are immediately driven to seek the fulfilment of our psychological and social needs. The fulfilment of these needs isn’t an optional extra; it is crucial to our human thriving.

In a study titled Psychological Needs Satisfaction and Attachment to Natural Landscapes, researchers demonstrated that the reason individuals develop attachment to wilderness areas (that is, have ‘special’ wilderness areas that they like to visit repeatedly) is because being in these wild places meets their basic psychological needs for autonomy, relatedness, and competence.

In turn, the authors argue, the fulfilment of these needs promotes positive mental and physical health outcomes and improves healing.

Australia’s public health policy is currently myopically focusing on a quixotic attempt to prevent all deaths from SARS-CoV-2 infection.

But the attempt to preserve biological life at all costs, even in individuals whose life expectancy is limited by advanced age or terminal illness, has resulted in diktats that deny individuals the ability to meet their needs for meaningful occupation, connection with others, self-determination and creative self-expression.

Not only is this perverse and anti-human – what is the point of preserving life, if everything that people live for has been stripped away from them? – it is also counterproductive in that people who are deprived of their psychological and social needs are more susceptible to infection, more likely to become seriously ill, and more likely to die.

5. Green spaces in urban areas reduce violent crime

Access to green spaces, including parks, botanical gardens, urban forests and community gardens, reduces violent crime including gun violence.

A fascinating paper titled ‘The Impact of Green Space on Violent Crime in Urban Environments: An Evidence Synthesis‘ explains why.

• Green spaces provide venues for cohesion-promoting social interaction. Residents who perceive their neighbourhoods as ‘greener’ also perceive their neighborhoods as being safer and having stronger social ties.
• Green spaces provide opportunities for recreational activities that present children and adolescents with attractive alternatives to gang membership.
• Parks and other green spaces provide attractive settings for physical activity, which reduces stress, in turn mitigating mental illness that might be associated with violent behaviour.
• The ‘biophilic support’ provided by nature reduces stress, improves perceived quality of life, and promotes restoration and resilience – all of which decrease the likelihood of perpetrating violent crime.
• Community-developed green spaces enhance the sense of community ownership, enfranchisement, civic pride and perceived order, diminishing the likelihood of crime.
• Green spaces reduce ambient temperatures; fascinatingly, higher temperatures (up to 32°C) are associated with increased aggression.

Hopefully, officials who are grappling with riots and looting will get the memo, and ramp up funding for the creation and maintenance of green spaces in urban communities beset with divisive issues that have reached flashpoint in the economic meltdown generated by the world’s response to SARS-CoV-2.

6. Feeling connected to nature makes children happier

One of the greatest injustices of most governments’ response to the emergence of SARS-CoV-2 has been that children, who have a close to zero risk of being infected by, becoming ill from, or transmitting the virus to others, are being deprived of the social contact that is foundational for their healthy development and psychological well-being.

A feeling of being connected to nature – which rests on the ability to actually experience it – has been found to be linked to happiness in children.

Children who are being cruelly and unnecessarily starved of vital social contact through school closures, cancellation of sports, dance classes and other recreational activities, and prohibitions or severe restrictions on birthday parties should not be further tortured by being deprived of the opportunity to play outdoors in green spaces.

7. Sitting still is linked to depression in adolescents

Rates of depression in teenagers were already at worrying levels before SARS-CoV-2 appeared, but school closures, physical distancing and home confinement orders have propelled them to dizzying heights.

With routines completely disrupted, parents are worriedly reporting that their adolescents are locking themselves in their rooms and barely moving for weeks.

The tendency of children to become less active as they progress through adolescence has been severely exacerbated, and this trend toward increased sedentariness has been strongly linked to an increased risk of developing depression.

Since access to green spaces is conducive to enjoying physical activity, adolescents should be encouraged to spend more time in nature, in order to promote both physical and mental health.

The bottom line: Nature is powerful medicine

Given the impressive evidence of the benefits of exposure to green space to both physical and mental health, and the exceptionally low risk of transmission of SARS-CoV-2 in outdoor settings, it’s difficult to comprehend why public health officials ordered the closure of parks, playgrounds and other outdoor venues that provide opportunities for us to interact with nature, and the imposition of fines for sitting, even alone, in outdoor green spaces.

In the midst of a global pandemic of a contagious respiratory virus, it’s good public health policy to promote activities that enhance our immune system’s capacity to defend itself against viral infection while restraining the ‘friendly fire’ overactivation that can lead to damaging and even deadly cytokine storms.

Time spent in nature would be just what the doctor ordered, if that doctor had any clue whatsoever about immune function.

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