Pregnancy relaxation outdoors

By Sandy Hemphill, Contributing Writer, BabyMed

Many studies have been done on how time spent outside, visiting with Mother Nature, improves certain diseases and chronic health conditions such as cancer, depression, cardiovascular disease, obesity, diabetes, and musculoskeletal conditions. Most studies focus on just one medical condition but a University of Illinois researcher thought there might be a single common thread that produced benefits to so many diseases and she found it. Spending time in nature strengthens the immune system, according to Ming Kuo.

Kuo, an environment and behavior researcher who serves as director of the university’s Landscape and Human Health Laboratory, pored through hundreds of studies that explored the effects of nature on human health. Her search revealed no fewer than 21 possible pathways between good health and Mother Nature. All but two of these pathways shared a common element: they enhanced the function of the immune system.

Huge, Broad Effects on Health

Time in the great outdoors has been found to protect the health of many human body systems — cardiovascular, mental health, musculoskeletal, respiratory, and more — all at the same time in a way that Kuo likens to a multivitamin. Multivitamins provide a wide array of nutrients and Kuo says this is exactly how nature protects us, too. Like multivitamins, “nature doesn’t just have one or two active ingredients,” she said.

“The realization that there are so many pathways helps explain not only how nature promotes health, but also why nature has such huge, broad effects on health,” she said.

Rest and Digest

The “fight or flight” response to stressful situations has long been understood. When confronted with a problem (saber-tooth tiger, charging elephants, tough tests at school, bankruptcy, missed job promotions), the body is flooded with stress hormones that heighten our awareness of every little thing in our environment. It all becomes a big deal. We become ready to fight it out or run for our lives. Every body system not required for immediate survival is put on temporary hold, including the immune system.

Kuo thinks time in nature turns that high-stress switch off and turns on a “rest and digest” switch that allows the body to relax and recover. She says, “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.”

Full-Blown Restoration Occurs Outside

Any time we feel safe, relaxed, and peaceful, the entire body benefits but Kuo says full-blown restoration occurs outside. Pleasant indoor activities help but it’s only outside that we encounter certain important elements in abundance. Kuo says, “Enjoyable indoor activities don’t provide the phytoncides, mycobacterium vaccae, negative air ions, vitamin D-producing sunlight, and other active ingredients found outdoors. So we’d expect a smaller boost than you’d get from being in nature.”

“Finding that the immune system is a primary pathway provides an answer to the question of ‘how’ nature and the body work in concert to fight disease,” Kuo said.


  1. Levey Larson, Debra. "Immune system may be pathway between nature and good health." ACES / College News. Board of trustees University of Illinois, 16 Sept. 2015. Web. 23 Sept. 2015.
  2. Kuo, Ming. "How might contact with nature promote human health? Promising mechanisms and a possible central pathway." Frontiers in Psychology (2015). Web. 23 Sept. 2015.