Health and Nature

Current State of Affairs

How much time have you spent outdoors this week? For most Canadians and Americans, the answer is “not much.” Currently, North Americans spend 95% of their day indoors or in a vehicle. In addition, we’re spending a lot of that time engaged with technology. The average child spends six minutes per day doing outdoor activities and six hours using a computer or watching television.^[1]

In the last 50 years, the amount of time spent in green spaces has declined by 50%. It’s no surprise that 77% of North Americans are deficient in vitamin D—a hormone synthesized in the skin in response to sun light.^[1] But what if there’s something else that all of these people are missing out on as well—say a “vitamin N”? Research is rapidly mounting to support the hypothesis that spending time in nature plays a vital role in our health, both physical and mental. Traditional healers from Ayurveda, the Indian medical system, and traditional Chinese medicine have endorsed nature exposure as a form of medicine for well into their histories. Well-known American naturalist and conservationist John Muir advocated in the late 1800s for individuals to spend time away from the modern civilization and connect with nature for their mental wellbeing.^[2] While this may be intuitive and practiced for centuries, it’s only recently that Western medicine has started to take note. In 1984, a researcher observed that individuals recovering from gallbladder surgery had different recovery times and different use of pain medication based on which side of the hall their room was located. One side overlooked a cluster of tress while the other side faced a wall ^[2]—very intriguing. Scientific technology is developing in ways that allow us to understand the mechanisms, magnitude, and precise effects of nature exposure on our health. For example, we are able to observe changes in brain activity when participants look at different images. When someone looks at an image of an urban landscape, areas of the brain associated with stress and fear are activated. In contrast, looking at scenes of nature activates areas of the brain associated with emotions of stability and love.^[2]

Effects of Nature on Physical Health

The effects of spending time in nature on our physical health appear to be broad and of very substantial impact. Nature-exposure interventions have been associated with reductions in blood pressure and sugar, improved immune function, and reduced obesity.^[2] The magnitude of the impact on the health of individuals is becoming known as well. One study compared two sets of data from the city of Toronto and determined the number of trees planted on the streets as well as the health of the residents. After accounting for factors such as income, age, and education, an additional ten trees on a street corresponded to a 1% improvement in how healthy the residents felt. Now this might not sound like much, but to achieve a similar improvement by adjusting age, you would need to make people seven years younger. The data also showed a connection between more trees and lower rates of heart disease, stroke, and diabetes.^[3]

Effects of Nature on Mental Health

We know that nature exposure also affects our cognitive and emotional wellbeing. Studies have demonstrated improvements in stress ratings as well as anxiety and depression symptoms, improved impulse control, improved cognitive function, improved workplace performance in adults and improved academic performance in children, and improved memory and focus. There is also evidence of improved creativity, curiosity, and problem-solving ability.^[2] One recent study from Stanford University compared a 90-minute walk in a grassland to a walk beside a busy highway and found significant differences in the brain-scan findings. The nature exposure was associated with a decrease in activity in the brain region active during rumination, a repetitive focus on negative emotions.^[4] Another fascinating area of research with respect to nature and mental health has to do with soil microorganisms. New research abounds on the relationship between beneficial bacteria and healthy mood. A mouse study found that exposure to a common, harmless soil bacteria improved scores in a test used to measure depression. This is leading to a call for people to “get their hands dirty” as part of their treatment for mood disorders including time in nature and gardening.^[2]

How to Incorporate Into Your Life

The great news about this powerful intervention is that it’s accessible to everyone and can be used for free. There are many ways to incorporate nature exposure into life: this can include small daily efforts such as choosing to walk in a natural environment, like a park, forest or conservation, instead of a subdivision or commercial area; taking a lunch break outdoors; or choosing to sit facing a window with a view of the outdoors. Consider ways to interact with the nature too like gardening (even a planter on your balcony or volunteering to get your hands dirty weeding a friend’s yard). Now you might say that you’re not that fond of these activities and that’s actually alright. One study, conducted in Michigan, showed that a boost in memory and attention following a nature walk was equal in magnitude in both June and January walking groups, despite the January group finding it less enjoyable. Also consider opportunities for longer exposures to nature as the dose of this intervention matters. One study found that two days spent in nature increases white blood cells by 50%,^[2] and another found that three days in nature boosts creativity by 50%.^[5] This might be hiking or camping in a provincial park, or planning a vacation that allows you to be outdoors.

In order to get the most out of your time in nature, try to give it your full attention. We get the full benefits of time in nature through a combination of our senses. Studies have identified mechanisms for the effect of nature sounds, images, scents, and physical sensations.^[2] In order to take it all in, this means leaving the smartphone or headphones at home. Also, time in nature can be combined with mindfulness, the practice of paying attention to the present moment for further additive, cognitive, and emotional benefits, or combined with exercise for additional physical and mental benefits.