Newsletter #135: Health and Happiness Through Nature 🌲
Welcome to the latest edition of the humanOS newsletter!
This week, we learned that adding plants to peoples’ front yards is linked to reduced subjective stress as well as better stress regulation; regular exposure to nature - either by going outside or even just viewing greenery from a window - is associated with better mental health in the midst of the coronavirus pandemic; and these improvements in mental health and stress regulation may be due to activation of specific regions of the brain that are responsive to green space.
Scroll down to learn more 👇
This Week’s Research Highlights
🏡 Green plants in your front yard may reduce physiological and psychological stress.
Researchers introduced ornamental plants into previously bare front yards in an economically deprived region of North England. They followed the residents of these homes for three months after the intervention, as well as a comparator group who did not receive plants (controls). After the plants were installed, residents reported significant decreases in perceived stress. This was accompanied by improvements in diurnal cortisol patterns, as the proportion of residents with “healthy” cortisol patterns increased from just 24% up to 53% after the horticultural intervention, suggesting a reduction in physiological stress and better stress regulation. Further qualitative data indicated that the residents valued the gardens as enhancing relaxation and increasing their pride in their homes.
😷 A regular dose of nature may shield mental health during the pandemic.
Researchers conducted an online survey (n = 3000) in Tokyo to assess the relationship between mental health outcomes and two different measures of nature experiences (frequency and duration of greenspace use, like forests, parks, etc, versus viewing greenery through windows at home) during the coronavirus pandemic. After adjusting for socioeconomic and lifestyle variables, the researchers found that self-esteem, life satisfaction, and subjective happiness were all positively correlated to exposure to greenspace use as well as green views through windows. People with more frequent greenspace exposure also exhibited lower levels of loneliness and anxiety. The pandemic has created a stressful environment all over the world, and nationally representative surveys suggest that the number of adults experiencing depression has risen three-fold in the US. Encouraging people to go to a park (while socially distanced), or even just sit by a window, seems like an easy and safe way to slow the recent escalation of mental health disorders. As an added bonus, prior research suggests that regular exposure to green space may also promote beneficial changes to the immune system in older adults as well as in children.
🧠 Viewing green space elicits activity along a network of regions in the brain involved with attention and stress regulation.
Lots of studies have suggested that people exposed to green space report lower levels of stress. But why? To gain some insight into underlying mechanisms, researchers used functional magnetic resonance imaging (fMRI) to examine the brain activity of 44 participants as they viewed images of urban areas that varied in density of green space. Some pictures had lots of trees and bushes, some were mostly sidewalks and buildings, and others were somewhere in between. Two weeks later, participants returned to the lab to analyze their stress levels, as well as preference ratings for landscape images. The scientists found systematic differences in brain responses based on the green-space density of the urban images that the participants had viewed. Specifically, urban landscapes with varying levels of green cover elicited corresponding changes in the activity of the posterior cingulate, a part of the brain that is involved with a wide array of functions, but in particular, has connections to attentional nodes in the brain.
Furthermore, these changes were in turn correlated with changes in metrics of stress in the subjects. It appears that the posterior cingulate is a key component of human sensitivity to green spaces, and through a cascade of responses ultimately interfaces with stress regulatory responses within the brain.
Question of the Week
Are you exposed to “green” environments regularly during the week? If not, is there something relatively easy you can do to increase your dose of nature (maybe move your workstation next to a window, or head to a nearby park to get your steps)?
Podcasts We Loved This Week
- Ming Kuo: Our Better Nature - How The Great Outdoors Can Improve Your Life. Via Hidden Brain.
- Herman Pontzer: Constrained Energy Expenditure Model & the Evolutionary Biology of Energy Balance. Via Sigma Nutrition.
- Akiko Iwasaki, Alessandro Sette, Shane Crotty: Can You Get COVID-19 More Than Once? Via Science Friday.
Products We Are Enjoying
Oatly
Probably my favorite non-dairy milk. Really delicious, great mouth-feel, tastes good in coffee, tea, or just by itself. It’s also a safe pick from a nutritional standpoint: free of added sugar, thickeners, or gums, and a good source of beta-glucans, calcium, and vitamins A and D. You should be able to find it in stores - I’ve gotten it at Target - but you can also order online if it’s not available in your neck of the woods.
New humanOS Course
Female Sports Nutrition
Of course, many aspects of sports nutrition are the same for both men and women, and plenty of people have done well just applying the same general guidelines across both genders. However, there are a few noteworthy differences, and better understanding of these unique considerations can lead to improved training and greater success in competition.
In this course, we cover female hormones, optimizing energy intake, specific micronutrients that are often a concern for female athletes, how to maintain optimal hydration, how to plan training at different points in the cycle, and how to avoid health issues associated with inadequate energy availability (female athlete triad). If you are a woman who trains regularly, or if you coach women/girls, this course should prove to be a useful resource for you.