Time spent close to nature is good for our health, numerous studies have shown. What is much harder to establish, however, is how and why this occurs. Now a paper claims the immune system may be the primary pathway through which exposure to the natural world can lead to a wide array of health benefits.
Modern medicine and plumbing – which brings us clean water and removes our waste – have doubled our lifespans, but technology sometimes comes with a cost to our health. It seems urban living is part of that, with research linking lack of access to the open air and relatively pristine environments to an astonishing range of conditions from depression and ADHD to cancer. The effect nature is thought to have on us has earned the name Biophilia. Now a paper attributing these diverse benefits to the immune system has been published in Frontiers of Psychology.
Ming Kuo of the University of Illinois, Urbana-Champaign, isn't jumping to conclusions. As the author of some of the papers indicating these benefits herself, she uses the review article to propose 21 pathways that might connect time in nature with better health.
“While each is likely to contribute to nature’s impacts on health to some degree and under some circumstances, this paper explores the possibility of a central pathway by proposing criteria for identifying such a pathway and illustrating their use,” Kuo writes. “A particular pathway is more likely to be central if it can account for the size of nature’s impacts on health, account for nature’s specific health outcomes, and subsume other pathways.”
Her conclusion is that “enhanced immune functioning emerges as one promising candidate for a central pathway between nature and health. There may be others.”
"Nature doesn't just have one or two active ingredients. It's more like a multivitamin that provides us with all sorts of the nutrients we need. That's how nature can protect us from all these different kinds of diseases – cardiovascular, respiratory, mental health, musculoskeletal, etc. – simultaneously,” Kuo said in a statement.
Kuo suggests that fresh air, sunlight and a beautiful view relax us and turn off our “fight or flight” responses. “When we feel completely safe, our body devotes resources to long-term investments that lead to good health outcomes – growing, reproducing, and building the immune system,” she said. If so, many of the same benefits can be achieved for those who really aren't the outdoor type by doing what they love, be it reading a good book or spending time with friends. However, Kuo adds these don't provide elements of good health such as Vitamin D.
Some of Kuo's previous work has looked at the ways cities can be redesigned to maximize the health benefits provided by relatively natural environments, even if provided in the limited format of urban parks or community gardens. A better understanding of the mechanisms might help us understand how to fit nature into our busy lifestyles, if that is not too much of a contradiction. Still, we hope you're reading this on a mobile device in a forest or at the beach.