Want to feel better, improve your mood, boost your brain function, and lessen the chances of contracting a disease, including cancer? The Japanese have discovered and incredibly simple and enjoyable way to do all these things: Take a stroll in the woods. That's a stroll--not a hike, not a rock climb and not even a guided educational nature walk. To get the full benefits, you have to give up the American tendency to be goal-oriented and just be in in the middle of nature, letting it fill up your senses.

For the Japanese, of course, communing with nature is a major element of their culture and belief system--think Cherry Blossom Festival. So it's not surprising that they've devoted the time and funding to thoroughly study the effects of nature on the human system, resulting in their practice of shinrin-yoku, which translates roughly as "forest bathing."

First popularized in Japan in 1982, forest bathing is now a widespread pastime in Japan and is growing in popularity here too. Some American certified forest therapy guides (yup, that's a thing) believe shinrin-yoku is poised to become as big an element of American wellness as yoga and meditation are--two other Eastern practices scientifically proven to promote brain function and health.

The concept that forest bathing can have health benefits may have you rolling your eyes but it's perfectly believable to me. I spent most of the last 20 years living in rural upstate New York--I didn't have to go to the forest; it was right outside my door. I did occasionally have to go to New York City, which is where I grew up and a place I've always loved. I was always happy to go but there was that incredible moment when I stepped off the train home and took my first breath of tree-infused air. My whole body would react with what felt like relief and joy.

If that's too unscientific for you, consider these facts:

1. Spending time in nature has been proved to improve brain function.

The most dramatic effects, one researcher says, occur on your third day in an natural environment, but shorter nature visits work too. If you've ever had the common experience of finding the answer to a difficult problem while walking in the woods or a park, that's why.

2. Walking in nature has been shown to improve mood.

There's a thing called "rumination," which is the scientific term for the human inability to stop thinking about something that's upsetting or stressing us. Rumination is measurable in a part of the brain called the subgenual prefrontal cortex. Interestingly, a 2015 experiment showed that urban dwellers who walk in nature experience a decrease in rumination, whereas a similar group of urban dwellers who go for a similar walk in an urban environment see no such decrease.

3. Being in nature measurably reduces stress.

As you likely know, stress can kill you in oh-so-many ways, including affecting your brain, heart disease, digestive disease, and lowering your immune function. If you've ever taken a walk in a forest, garden, or park, you've probably noticed the stress-busting effects of being in nature. Scientists have noticed them as well. A 2010 study in Japan showed that forest bathing reduced heart rate, blood pressure, and the stress hormone cortisol. Other studies in the U.S. and Finland came up with similar results.

4. Forest bathing boosts your anti-cancer cells.

If none of this convinces you that walking in the forest is a good idea, consider this: Japanese researchers found that forest bathing boosts subjects' immune systems, including their "natural killer" cells. Natural killer cells are the ones that strike out diseases before they take hold and kill cancer cells before tumors can form. Of all the cells in your body, you particularly want these to be plentiful and healthy. Japanese subjects who went on a three-day forest excursion saw their natural killer cell activity increase by an impressive 50 percent.

In fact, this boost in natural killer activity is how nature trails are judged in Japan. The Japanese perform blood tests on subjects who walk the trails, and only those that produce a significant killer cell increase are certified as official shinrin-yoku places. In fact, the Japanese take forest bathing so seriously that it is covered by health insurance, according to one U.S. practitioner.

Makes sense to me.