When my editors asked me to report on forest bathing, I packed a swimsuit. I assumed it must involve a dip in the water.
It turns out, my interpretation was too literal.
I met certified Forest Therapy guide Melanie Choukas-Bradley and several other women who'd come along for the adventure at the footbridge to Theodore Roosevelt Island, a dense jungle of an urban forest along the Potomac River in Washington, D.C.
Here, I began to get it. Forest bathing isn't a bath. We sat on the banks of the river, but we did not get in the water.
It's not a hike, either. We did walk the forest trails, but we meandered with no particular destination in mind.
The aim of forest bathing, Choukas-Bradley explained, is to slow down and become immersed in the natural environment. She helped us tune in to the smells, textures, tastes and sights of the forest. We took in our surroundings by using all our senses.
As we passed through a stand of pawpaw trees, we touched the bark. We smelled the black walnuts, which give off a lovely citrus fragrance. We got a little shower of ripe mulberries, too.
"Close your eyes and just breathe, just breathe," Choukas-Bradley intoned. It felt a bit like a meditation retreat.
It took me a few minutes to clear out the clutter in my brain, and tune in to the natural world.
"When you open your eyes, imagine you're seeing the world for the very first time," Choukas-Bradley told us.
After I opened my eyes, the green looked a lot greener. And I began to see things I hadn't noticed before: the flutter of birds, the ripple of the water, the swaying of trees.
A forest guide "helps you be here, not there," says Amos Clifford, a former wilderness guide with a master's degree in counseling, and the founder of the Association of Nature & Forest Therapy, the organization that certifies the guides.
Clifford's goal is to encourage health care providers to incorporate forest therapy as a stress-reduction strategy. There's no question that stress takes a terrible toll in the United States; a 2015 study found work-related stress accounts for up to $190 billion in health care costs each.
"It's my hope that the health care system will include [forest therapy] into the range of services they reimburse for," Clifford says.
The practice began in Japan. Back in the early 1990s the Japanese Ministry of Agriculture, Forestry and Fisheries coined the term Shinrin-yoku — which translates roughly as forest bathing.
Now, forest bathing is starting to take off in the U.S. The Associations of Nature & Forest Therapy plans to train and certify about 250 new guides next year. "We're aiming to have 1,000 trained guides within three years," Clifford says.
There's a growing body of evidence that the practice can help boost immunity and mood and help reduce stress. "Medical researchers in Japan have studied forest bathing and have demonstrated several benefits to our health," says Philip Barr, a physician who specializes in integrative medicine at Duke University.
One study published in 2011 compared the effects of walking in the city to taking a forest walk. Both activities required the same amount of physical activity, but researchers found that the forest environment led to more significant reductions in blood pressure and certain stress hormones.
On average, the forest walkers — who ranged in age from 36 to 77 — saw a reduction in their systolic blood pressure from 141 mmHg down to 134 mmHg after four hours in the forest.
This might not sound like a big difference, but it can be clinically significant. Most doctors these days agree that people younger than 60 should aim to keep their blood pressure under 140.
"I'm very impressed with the primary research done in Japan," Barr says. He thinks many patients could benefit from forest bathing, especially those who are under stress.
"Forest bathing could be considered a form of medicine," Barr says. "And the benefits of nature can be accessed so simply."
It's not a big surprise that researchers were able to document a decrease in blood pressure among forest bathers. As people begin to relax, parasympathetic nerve activity increases — which can lead to a drop in blood pressure.
There's another factor that might help explain the decline in blood pressure: Trees release compounds into the forest air that some researchers think could be beneficial for people. Some of the compounds are very distinctive, such as the scent of cedar. Back in 2009, Japanese scientists published a small study that found inhaling these tree-derived compounds — known as phytoncides — reduced concentrations of stress hormones in men and women and enhanced the activity of white-blood cells known as natural killer cells .
Another study found inhalation of cedar wood oils led to a small reduction in blood pressure. These are preliminary studies, but scientists speculate that the exposure to these tree compounds might enhance the other benefits of the forest.
The idea that spending time in nature is good for our health is not new. Most of human evolutionary history was spent in environments that lack buildings and walls. Our bodies have adapted to living in the natural world.
But today most of us spend much of our life indoors, or at least tethered to devices. Perhaps the new forest bathing trend is a recognition that many of us need a little nudge to get back out there.
ROBERT SIEGEL, HOST:
As we've heard, Senator John McCain is recuperating from neurosurgery. He had a blood clot removed from over his eye. And to learn more about the kind of surgery he underwent, its risks and what a recuperation might be like, we turn now to Dr. Peter Nakaji, who is director of the neurosurgery residency program at the Barrow Neurological Institute in Phoenix. Welcome to the program.
PETER NAKAJI: Thank you, Robert.
SIEGEL: And we should say you are not treating Senator McCain. We're just calling you as someone who does this kind of work. Senator McCain's office describes the procedure as a minimally invasive craniotomy with an eyebrow incision. What does that mean?
NAKAJI: So there are a lot of ways to get into the head, and some are more invasive, and some are less. And what that really means is that instead of making a large opening in the head and opening a large window through the skull, we make a small one right over the eye through the eyebrow and open a little window and really make a direct route to whatever we need to get to, assuming it's right under that spot. So that's a less-invasive, easier-to-recover-from kind of surgery.
SIEGEL: The blood clot was described as 5 centimeters or about 2 inches. Is that average, relatively large, small? And what danger would it have posed?
NAKAJI: So as you point out, I'm not a treating physician, so I don't have all of the information. And the real key is 5 centimeters in which direction. So something which is 5 centimeters around is actually pretty big for the frontal lobe, whereas if it's shaped like a pancake, it's not very big. So if the blood is outside the brain, it may not be that impactful. If it's inside, it may or may not be impactful. It really matters a bit more what it's caused by.
SIEGEL: But when you use the word impactful in this case, what kind of impact are you alluding to?
NAKAJI: Well, the left frontal lobe in most people is considered the dominant one, meaning it's responsible for a lot of high-level thinking. And if you're a very high-functioning person like he is, a lot of things like judgment and speech can be in that area. Happily, it sounds like he was out quickly and doing very well, so it may not have had a lot of impact. Draining a blood clot that expands like a balloon and then deflates like a balloon sometimes can be recovered from very well.
SIEGEL: Well, obviously much depends on the details here of the blood clot, but how long might it typically take, say, a robust 80-year-old to recover and be back on the job?
NAKAJI: Yeah, well, fortunately he is a very robust 80-year-old. He's in good shape, and that's where I like to start. I mean reasonably we would send someone home in a day or two, which nowadays for this kind of minimum-invasive neurosurgery is realistic. But I wouldn't counsel anybody to go back to normal activity for at least two weeks. And many people may take even four to six weeks to feel really up to snuff.
SIEGEL: Yeah. We're told that tissue pathology reports are pending within the next several days. What are the answers doctors are looking for there?
NAKAJI: Well, I think what we're all hoping to see for the sake of Senator McCain is that we don't see something underlying like the melanoma that we know is in his history. This is one of the tumors more likely to bleed in the brain. And we'd like to see that that's not it and that it's something else. But you know, pathology - we get it because we don't know what it'll show to be sure.
SIEGEL: After Senator McCain's melanoma, which was over 15 years ago, he said that he was being followed very closely. Would that mean regular scans? And would that mean that something grew to this size even despite his being looked at very recently?
NAKAJI: Yeah, surprisingly we do see bleeding in the brain. You know, the brain is not sensitive to pain, so you can see things expand without really seeing them happen, sometimes to rather alarming sizes. And we do see it all the time. So the fact that they would be looking a little bit more at him because of his history might have mean that they did pick it up and it did get to be very big despite all. But it is hard to say without knowing a bit more about it.
SIEGEL: The only thing I would ask - and I would respect your not answering if you chose. But I'm just curious to hear...
SIEGEL: ...What you would say was. Not too long ago in his questioning of former FBI Director James Comey, Senator McCain betrayed a confusion in public. He later said, I was up late watching the Diamondbacks baseball game. Is there any link between confused speech or thinking and a blood clot of this size?
NAKAJI: Yeah, I mean I think in this case, it would be speculation because this might well have started after that for all we know. But if you had something in that location, I suppose it's possible - as I say, probably speculation at this point.
SIEGEL: That's Dr. Peter Nakaji, director of the neurosurgery residency program at the Barrow Neurological Institute in Phoenix, Ariz. Thanks for talking with us.
NAKAJI: Thank you. Transcript provided by NPR, Copyright NPR.