The Good of Green

In 2012, a group of backpackers embarked on a multi-day wilderness journey, free from technology. Before their adventure, they took a creativity and problem-solving assessment. After four days in nature, their scores increased by 50%, from an average of 4.14 correct answers to 6.08.

While the study couldn’t definitively establish cause and effect, the researchers from the University of Kansas and the University of Utah shared their hypothesis: modern life is filled with distractions that can overwhelm our focus. In contrast, natural settings promote a gentle and calming fascination, allowing our attention to rejuvenate.

"Spending time in, or living close to, natural green spaces is associated with diverse and significant health benefits," they concluded.

Other studies have shown that the benefits of green areas aren't exclusive to outdoor enthusiasts.

Back in 2006, research led by behavioral scientist Jolanda Maas at Vrije University Amsterdam revealed a significant relationship between the amount of greenery within a 2-mile radius and perceived health. This conclusion was drawn from the analysis of greenery levels against health questionnaires filled out by over 250,000 people in the Netherlands.

Maas and her team conducted a similar study in 2009, which examined morbidity data. Out of 24 diseases analyzed, the prevalence of 15 was lower among individuals living in greener neighborhoods, with the strongest correlation found for anxiety and depression, as reported in the Journal of Epidemiology & Community Health.

Moreover, access to green spaces has been shown to alleviate stress and pain in hospital patients, enhancing recovery and boosting the immune system. Similarly, gardening has been found to reduce stress levels more effectively than reading, according to a small study in 2011. Participants engaged in gardening experienced a greater decrease in cortisol levels than those who read.

Fast forward to a comprehensive review published last year, which analyzed data from over 290 million individuals in 20 countries.

"We found that spending time in, or living close to, natural green spaces is linked to various health benefits," said lead author Caoimhe Twohig-Bennett from the University of East Anglia. "It lowers the risks of type II diabetes, cardiovascular issues, premature death, and preterm birth while enhancing sleep duration. Additionally, those living near nature exhibited lower blood pressure and heart rates."

Nature or Nurture?

A crucial detail to consider in many of these studies is the relationship between being outdoors and physical activity. Whether hiking, gardening, or walking briskly in a park, participants often engage in moderate physical activity, which is known to enhance mood, cognitive function, and overall health.

"Those living near green spaces likely have more opportunities for physical activity and social interactions," Twohig-Bennett noted, recognizing the challenges in establishing direct cause-and-effect relationships.

The scientific community remains undecided on whether it is nature itself or the associated physical activity that contributes to health benefits. Douglas Becker, a graduate student at the University of Illinois, recently published a study examining the impact of nature on healthcare costs. He analyzed health data from nearly all U.S. counties, finding that those with more forests and shrublands had lower Medicare expenditures per capita. Each 1% increase in forest coverage correlated with an average savings of $4.32 in annual Medicare costs.

Becker's findings suggest that a national reduction of approximately $6 billion in Medicare spending could be achieved through increased forestation across the U.S.

So, should we plant more trees? While Becker's analysis does not conclusively establish a direct link between tree coverage and reduced healthcare costs, it adds to the growing evidence that green spaces, particularly forests, are beneficial for health.

"Being in sight of nature indeed provides advantages," he affirmed.

Twohig-Bennett also pointed to an intriguing potential benefit from her review of literature—exposure to diverse bacteria found in natural environments might boost the immune system and reduce inflammation. This aligns with research on "forest bathing," a popular practice in Japan that involves immersing oneself in a forest.

"Studies suggest that phytoncides—organic compounds released by trees—could explain the health benefits associated with forest bathing," Twohig-Bennett mentioned. While the efficacy of this therapy is still under investigation, she emphasized that existing studies may support its value.

All in Your Head

In 2015, researchers at Stanford University further established the distinct benefits of nature itself, independent of the exercise involved in reaching natural settings. They compared the effects of hiking in a natural area versus an urban environment. Participants' physiological responses, including heart rates and brain activity, were measured before and after each hike.

Though the physiological differences were negligible, those who hiked in nature reported reduced activity in the subgenual prefrontal cortex, the area of the brain linked to negative thoughts. This decrease is beneficial.

"This highlights nature's influence on emotional regulation, potentially explaining its mood-enhancing properties," stated lead author Gregory Bratman.

Co-author James Gross expanded on this, linking the findings to urbanization and rising mental health issues.

Recent studies indicate that growing up in greener environments can lower the risk of mental disorders by up to 55% in adulthood, according to a study involving nearly 1 million Danes.

"There is increasing evidence that the natural environment significantly influences mental health," stated study leader Kristine Engemann from Aarhus University.

The benefits of nature on child development are recognized by educators, leading to a notable increase in nature-based preschools and "forest kindergartens" in the U.S.

Nature Pill?

How much time in nature is needed to reap its benefits? While more time is generally better, a recent study indicates that even short intervals can be effective.

Research published in April 2019 found that spending just 20 to 30 minutes in a natural setting significantly reduces cortisol levels, the hormone linked to stress.

Participants in this study, who were urban dwellers, took breaks of at least 10 minutes in natural settings, avoiding physical exercise, reading, conversation, or phone use during these periods. The stress-relieving effects were most pronounced among those who spent 20 to 30 minutes outdoors.

"We know nature reduces stress, but this study clarifies how much time is optimal and what type of experience is most beneficial," said lead author MaryCarol Hunter from the University of Michigan. "For the best results in lowering cortisol levels, aim for 20 to 30 minutes in a natural setting."

Hunter and her team propose that healthcare professionals could prescribe a "nature pill" based on their findings.

Incorporated with physical activity, sufficient sleep, and a balanced diet, this "nature pill" could become a cornerstone of science-based well-being. While frequent trips to our fishing spot may not be feasible, there’s a hiking trail near our home that leads into the desert and up a mountain. We'll be sure to explore it.

The first video titled "Mental Health Benefits of Getting Outside" discusses how nature positively influences mental health and overall well-being.

The second video titled "The Health Benefits of Being in Nature for 10 Minutes" emphasizes the significant health advantages even brief encounters with nature can provide.