“Everybody,” Muir said, “needs beauty as well as bread, places to play in and pray in, where nature may heal and give strength to body and soul.”
Turns out they were ahead of their time. “Attention Restoration Theory” or ART, which posits that a walk in the woods helps refocus the mind and revive the spirit, has been a growing field of research for the past 20 years. New studies are quantifying the restorative powers of nature and suggesting how the restorative process works. 
It’s a practice that has been used for as long as recorded history. Religious orders from all over the world have used the the meditative walk in nature to focus the mind.
This is a line of research is one I’ll be keeping an eye on in the future…It’ll keep me taking myself outside and walking more often. After studying the papers listed in article, I headed out on my walking trail out back for an hours health break.
 Attention Restoration Theory Taps Nature’s Medicine | Smart Journalism. Real Solutions. Miller-McCune..