How “Nature Pills” Enhance Immunity, Heart Health, and More

“In every walk with nature one receives far more than he seeks” 

- John Muir 

The natural world has long been revered for its aesthetic splendor, a constellation of sights, sounds, and smells that soothe the mind and nourish the soul. Yet only recently have we begun to rigorously study the full extent of nature’s impact on our wellness.  

Scientific research has uncovered a myriad of benefits to be gained from immersion in the natural world, from hastened healing to strengthened immunity to better heart health. In this article, we'll take a close look at how "nature pills" – small doses of exposure to the natural world – can enhance our physical health.  

A Window View Predicts Faster Surgical Healing 

In the late summer of 1984, Dr. Roger Ulrich, a professor of architecture and a specialist in hospital design, conducted a study that would change the way we think about the role of nature in our healing. Dr. Ulrich had a hunch that even a small measure of greenery in a hospital setting could improve the outcome of surgical recovery.  

To test his hypothesis, he examined records of patients who had undergone a cholecystectomy - the removal of the gallbladder - and divided them into two groups. One group had a window view of a brick wall and the other of a vista of trees and bushes. The results were astonishing. The patients with the nature view had shorter post-operative stays, requested half the painkillers, and rang the nurse's bell half as frequently [1].  

This groundbreaking discovery has since been repeated in numerous clinical studies, leading many hospitals to incorporating green spaces to enhance patient outcomes.  

Enhanced Immunity 

What accounts for the accelerated healing in the study mentioned above?

One clue comes from a line of research investigating the effects of “forest bathing” on immune function. In a landmark 2010 study, Japanese researchers found that a 3-day forest-bathing trip, in which participants spent a few hours outdoors each day, increased the production of natural killer cells, one of the body’s first lines of defense against infections. Amazingly, this increase was detectable for up to 30 days following the trip, suggesting that exposure to nature has long-term immune boosting effects [2]. 

This doesn’t appear to be a single-study fluke. A 2019 systematic review and meta-analysis, which screened 971 studies, found that in all but two of them, forest bathing moved markers of stress and immunity in the right direction [3]. 

Reduced Blood Pressure, Better Heart Health 

Not only does immersion in the natural world boost immunity, but it also appears to powerfully enhance cardiovascular health.  

 An observational study conducted on German children found that the amount of green space around a child's home was a significant predictor of their blood pressure [4]. Independent of factors such as noise, pollution, or level of urbanization, the less green the surrounding area, the higher their blood pressure was likely to be. 

Experimental research performed in Britain found a similar link. Investigators divided primary school children into two groups: group one rode exercise bikes staring at a blank screen, and group two rode exercise bikes while viewing a film of others cycling in a forest. Fifteen minutes after the bout of exercise, investigators found the group that watched the forest film had significantly lower blood pressure than the group that did not [5]. 

Importantly, this effect isn’t confined to kids. Researchers in Japan have found that for patients with congestive heart failure, a four-day “forest bathing” retreat, when compared to four days of urban exposure, reduced blood pressure, boosted antioxidant activity, and blunted systemic inflammation [6]. 

Since high blood pressure is the primary modifiable risk factor for cardiovascular disease, these studies have real implications for people trying to get their hypertension under control. In addition to exercising, eating well, and managing stress, getting out into the natural world might be some of the lowest-hanging fruit available for folks trying to improve their heart function. 

Bottomline 

From the healing power of "forest bathing," to the calming effect of an expansive window view, exposure to the natural world has a profound ability to impact our health. As the scientific research continues to mount, one thing is clear: reconnecting with the great outdoors, in one way or another, should be a priority for us all. 

Video: Shinrin-Yoku, (Forest Bathing)

References 

[1] Ulrich, R. S. (1984). View through a window may influence recovery from surgery. science, 224(4647), 420-421. 

[2] Li, Q. (2010). Effect of forest bathing trips on human immune function. Environmental health and preventive medicine, 15, 9-17. 

[3] Antonelli, M., Barbieri, G., & Donelli, D. (2019). Effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker: A systematic review and meta-analysis. International journal of biometeorology, 63(8), 1117-1134. 

[4] Markevych, I., Thiering, E., Fuertes, E., Sugiri, D., Berdel, D., Koletzko, S., ... & Heinrich, J. (2014). A cross-sectional analysis of the effects of residential greenness on blood pressure in 10-year old children: results from the GINIplus and LISAplus studies. BMC public health, 14, 1-11. 

[5] Duncan, M. J., Clarke, N. D., Birch, S. L., Tallis, J., Hankey, J., Bryant, E., & Eyre, E. L. (2014). The effect of green exercise on blood pressure, heart rate and mood state in primary school children. International journal of environmental research and public health, 11(4), 3678-3688. 

[6] Mao, G., Cao, Y., Wang, B., Wang, S., Chen, Z., Wang, J., ... & Yan, J. (2017). The salutary influence of forest bathing on elderly patients with chronic heart failure. International journal of environmental research and public health, 14(4), 368.