Giving Compass' Take:

• Researchers from the University of Michigan found that just 20 minutes of exposure to nature significantly lowers stress hormones within individuals.

• This study shows clear health benefits after spending time outside.  How can donors work to support nonprofits that are increasing access to outdoor opportunities?

• Read more about green spaces and their physical and mental health benefits.

A new study reveals that for urban dwellers, spending just 20 minutes with natural elements significantly lowers stress.

Have you heard about "nature pills" and "nature prescriptions"? After repeated studies have concluded that contact with nature reduces stress and improves well-being, doctors have started "prescribing" time spent outside.

But while we know it works, the parameters have been a bit murky: What kind of nature works? How often should one spend time in nature? And for how long? With this in mind, researchers from the University of Michigan set out to discover the relationship between the duration of a nature experience (NE), and changes in two physiological biomarkers of stress – salivary cortisol and alpha-amylase.

For eight weeks, 36 urban dwellers were asked to have a NE at least three times a week for a duration of 10 minutes or more.

To measure stress, levels of the stress hormones were measured from saliva samples taken before and after a nature pill.

What they found was that just a twenty-minute nature experience was enough to significantly reduce cortisol levels. And even better, if you bump that up to between 20 and 30 minutes, cortisol levels dropped at their greatest rate. After that, de-stressing continues, but more slowly.

Hunter says that we know that spending time in nature reduces stress, but until now it was unclear how much is enough, how often to do it, or even what kind of nature experience will benefit us.

This is such valuable research because now doctors can have measurable standards for which to prescribe nature pills.

Read the full article about nature can lower stress by Melissa Breyer at Treehugger.