Your average walk in the park may help you relax a little, but shinrin-yoku, developed in Japan in the 1980s, requires participants to deliberately engage with nature using all five senses. Portions of the walks are often done in silence, and cell phone use is discouraged. "I encourage walkers to practice deep breathing and to tune in to what sparks their senses, like the texture of birch bark or the scent of wild flowers or pinecones," says Mark Ellison, who began teaching shinrin-yoku classes three years ago at Cabarrus College of Health Sciences in Concord, North Carolina.
By combining mindfulness and spending time in nature—two activities that have restorative properties on their own—shinrin-yoku can yield significant health advantages: A study conducted across 24 forests in Japan found that when people strolled in a wooded area, their levels of the stress hormone cortisol plummeted almost 16 percent more than when they walked in an urban environment. And the effects were quickly apparent: Subjects' blood pressure showed improvement after about 15 minutes of the practice. But one of the biggest benefits may come from breathing in chemicals called phytoncides, emitted by trees and plants. Women who logged two to four hours in a forest on two consecutive days saw a nearly 40 percent surge in the activity of cancer-fighting white blood cells, according to one study. "Phytoncide exposure reduces stress hormones, indirectly increasing the immune system's ability to kill tumor cells," says Tokyo-based researcher Qing Li, MD, PhD, who has studied shinrin-yoku. Even if you don't live near a forest, studies suggest that just looking at green space—say, the trees outside your office window—helps reduce muscle tension and blood pressure.
Veteran wilderness guide Amos Clifford, who leads the walks that stressed-out Rebecca Valentine attends in California, knows just how healing shinrin-yoku can be: His blood pressure has dropped 10 points since he began forest bathing. "What we do doesn't seem in any way extraordinary, but the effects are astonishing," he says. For Valentine, the walks have become a sanity saver: "There are some great residual benefits. I won't say everything's fabulous, but when I leave the trail, I feel calmer, more reflective and refreshed. I feel like I'm taking care of myself in a way that has a lasting impact."