The new research, published in Frontiers in Psychology on 4 April, quantifies the benefits of spending time in nature.

By Daniel Herborn

Posted on April 5, 2019

While spending time in nature has long been associated with de-stressing and relaxing, the new research affirmed the value of ‘nature pills’ and determined how effective such ecotherapy can be.

The authors monitored the level of cortisol and alpha-amylase in subjects’ saliva to get a more detailed picture of this relationship. Cortisol is a hormone the body releases in response to stress and alpha-amylase is considered a possible biomarker of stress.

Plenty of informal evidence suggested time spent in nature reduces stress

In recent years, some doctors have taken to prescribing some time in a park or other natural setting (or ‘nature pills’) for patients presenting with conditions such as anxiety, depression and attention deficit disorder.

The authors note that a number of non-profit organisations have begun to offer nature activities for mood improvement and mental health assistance. These include the Mood Walks for Campus Mental Health program in Canada and the Coastrek initiative in Australia. A similar idea is ‘forest bathing’, a form of nature therapy that originated in Japan and has become increasingly popular in the Western world.

The 36 participants in the study were free to spend their time in nature as they saw fit but there were some rules; the activity needed to be done during daylight hours. Participants could not talk to others, read or use a mobile device while completing their experience.

The results are particularly salient as healthcare costs rise and urbanisation spreads, the authors noted. The United Nations has recently estimated that 60% of the world’s population will live in urban areas by 2030.

The World Health Organization has listed depression as the leading cause of disability worldwide. Some studies have suggested that living in urban areas may heighten the risk of depression and anxiety.

The work added to our understanding of the ‘nature pill’

Previous work in this field has often relied on self-reported data. The authors of this study wrote that they considered objectively sourced data preferable and chose the two biomarkers of stress they selected as they were able to be measured in a non-invasive way through saliva collection.

“Our ultimate goal is to articulate a “nature prescription” for use by healthcare providers as a preventive, self-administered health care treatment for mental well-being that is low in cost and effective in everyday settings,” the study explains. To this end, the work sought to identify what type of nature ‘pill’ was most efficacious, what ‘dose’ was necessary and how often it should be taken.

The study concluded the optimal length of time for a nature experience (NE) was between 20 and 30 minutes. After that, subjects continued to see benefits but they accrued at a slower rate.

The work was completed by Mary Carol R. Hunter, Brenda W. Gillespie and Sophie Yu-Pu, who are all based at the University of Michigan, Ann Arbor.

Header image credit: Luca Bravo