ParkBathe: The Awesome Science Of Forest Bathing

I'm Vanessa Potter,

And this is Finding Your Right Mind,

A podcast that champions citizen science and investigates the many different ways in which we can improve our own health and wellbeing,

Giving us less stressful,

More connected and happier lives.

Wouldn't that be a nice thing?

This is episode two of the Park Bathe series.

I promise some super cool science on forest bathing and here we are.

If you've dived right into this episode without listening to episode one,

I'll start by giving you a definition of forest bathing.

This is simply walking slowly and mindfully in nature while absorbing the woodland atmosphere.

Why that is good for us is yet to come.

This episode isn't just about the science though.

We're going to give you some practical and easy ways to bring the benefits of being in nature into your home.

Kirsten McEwen and I started the Park Bathe project in March this year,

And since then we have provided one hour guided forest bathing sessions in Crystal Palace Park to over 160 people as part of a citizen science initiative that was funded by the National Lottery.

Today we get to reveal the results from the wellbeing study that Kirsten has been running to see exactly what impact just one hour of slowing down and noticing nature had upon people's stress levels.

And while the term forest bathing might sound a bit woo woo and strange to some,

It's a deceptively simple practice.

Here are what some teenagers thought it might be and Kirsten explaining a bit more before one of our Park Bathe walks.

Okay,

Thank you everyone for joining us today on this forest bathing walk.

So when I say forest bathing walk,

What do you think we're going to be doing today?

Any thoughts?

Yes?

Walking?

Yeah.

Yeah.

Something to do with water.

Maybe.

Yeah.

Okay.

I'm assuming sniffing trees.

Sniffing trees.

We might do some of that.

Yeah.

Good suggestion.

Any other thoughts?

Yeah.

I got told we're hugging trees.

Who told you that?

Your parents.

We might be doing that,

But probably not.

You don't have to hug a tree unless you want to.

Any other thoughts about forest bathing?

What it might be?

Well,

It's really all it is,

Is a slow mindful walk in nature where we're just going to pay a lot of attention to our surroundings.

So we're going to be looking at.

.

.

When it comes to the science of forest bathing,

The trouble is deciding where to begin.

There is so much research into forest medicine as it's often known in Japan.

And that's probably the right way to think of it.

We'll show you how the forest really does offer up medicine for a variety of ailments,

Like the natural chemicals that trees give off called phytoncides,

And how breathing in these directly boosts our immune system.

I'm really excited that I got to talk to one of the leading researchers in this field.

I'm Dr.

Ching-Li from Tokyo,

Japan.

I'm studying forest medicine,

Forest bathing,

Xinyi-Yoku.

We'll hear from Quynh-Li later,

But perhaps the best way to relate to the science of the forest is to understand our own relationship with nature and trees.

I'm Stefan Batoris.

I run a company called Nature and Therapy UK,

Offering Shinrin-Yoku practitioner training courses.

And I also teach at Plymouth University on the Clinical Psychology Doctorate programme,

Teaching people about the benefits of nature as a recovery tool for mental health issues.

Nature leans over towards us a little.

Nature is always wanting to say hello to us.

And we're too busy because we're on a mobile phone or we're just walking along chatting.

And it's always leaning over to say hello,

And wanting to be friends.

And then if we can just stop,

Just slow down and actually connect with nature,

Then we have this opportunity for conversation and dialogue,

Which is really meaningful and supportive to us in our own lives.

As a child,

I played outside in the woods and the fields near my home in West Yorkshire,

And I can easily recapture that feeling of freedom,

Of running wild through bracken,

Climbing trees and hiding inside giant beach hedges.

I had an unconditional relationship with nature,

Except back then we just called it being outdoors.

There was no formal understanding that playing in nature was good for us.

Nature was our playground,

But you didn't talk about it.

What we know now is that nature changes us.

It rebalances us in whatever way we need it to.

And this is the clever thing.

Nature is intuitive.

It adapts to your needs.

So if you need your blood pressure to go down,

Being in nature will do that.

If you need your blood pressure to go up,

Nature will do that too.

Nature helps us think clearly.

It helps us relax and it brings us back to a comfortable baseline.

There's even research that suggests it makes us nicer people.

But before we get onto that,

Let's dive in.

And first of all,

Hear from Dr.

Yasu Kuterra,

One of Kirsten's colleagues at Derby University.

Hi,

My name is Yasu.

I am currently academic lead for counselling and psychotherapy at the University of Derby.

And as soon I'm going to be an associate professor for mental health at the University of Nottingham.

And I've been researching into mental health.

And one part of my mental health research explores shinrin yoku to see how that helps our mental health.

Yasu helps us understand why the Japanese use the rather confusing word bathing.

The word shinrin in Japanese means forest and yoku means bathing.

So from my Japanese understanding is that those words imply that like bathing in hot water,

That you go into nature and you are immersed with nature,

A forest.

And then this is probably a Japanese connotation that this sense of bathing yoku also implies harmonisation,

Harmonising with hot water,

Harmonising with sun,

That's sunbathing,

Harmonising with forest.

The aspect is kind of indicated in this word.

Many British people have a problem with the term forest bathing.

And Kirsten,

You did too,

Didn't you,

When you first came across this within your work?

Definitely.

When I first heard about forest bathing about eight years ago,

It just sounded a bit like a new age hippie practice.

And with my research scientist hat on,

It just it sounded a bit too woo woo.

But I was also a bit sceptical because I already spent a lot of time in nature and really enjoy being in nature.

So I wasn't really sure how this additional practice could really add anything else.

And then was really struck by how profoundly different it is to walk slowly through your environment and really notice your surroundings rather than just passing through it as an observer.

Which is really interesting,

Because actually,

We had quite a lot of people that struggled with the name,

Didn't we?

Yeah,

We did,

Particularly our male participants in Park Bathe.

They were a bit confused and thought that we were going to ask them to go skinny dipping in the woods.

Which was interesting,

Because some of them were obviously horrified at that.

And some of them are quite intrigued.

Yeah,

I think a few people came over to speak to us because they thought we were going to offer some wild swimming in Crystal Palace Park.

Yeah,

Which actually is quite fascinating.

What piece of research changed your mind?

There must be like one that just blew your mind.

I suppose when I first heard the term,

I didn't really know that much about forest bathing.

And when I did look into the research,

The amount of evidence for it was absolutely overwhelming.

There's just hundreds of papers on forest bathing now.

And quite a lot of them were showing evidence that it improved heart rate variability.

So that's the balance between our fight,

Flight or sympathetic nervous system and our rest and digest or parasympathetic nervous system.

And it's really a lot of research by Professor Miyazaki's team,

Which has repeatedly shown that just spending 15 minutes either walking in forests or looking at a view of a forest could increase heart rate variability in over 80% of people who they tested.

So with that kind of reliable evidence and it being shown repeatedly across many different studies and across many different forests as well.

So they published a paper about looking at heart rate variability in 24 different forests in Japan.

And they replicated that finding many times.

So it's not just a fluke.

That's the key,

Isn't it,

In science that it's replicable and it's robust.

So it convinced you.

Yeah,

Definitely.

And then my own research study in the UK,

We measured heart rate variability as well.

And we weren't expecting as stronger results as they do get in Japan,

But we still managed to get a really significant increase in heart rate variability of 12% improvement after just two hours forest bathing.

Why didn't you expect as big of results as the Japanese studies?

Cultural differences.

So in Japan,

They've got this cultural background of Shintoism and Buddhism.

There's already that deep connection and respect for nature that perhaps we don't have here.

So I wasn't really sure whether it would be as potent in the UK.

When I spoke to Yasu,

He talked about this cultural divide as well,

Which is really,

Really interesting.

I was thinking about a difference of Western science and Eastern philosophy.

Science implies it's about dissecting.

So if there is a symptom,

One patient doesn't feel good,

You dissect and then finding out which part exactly is causing this distress.

So it goes to very specific point.

And then that's how science develops.

While Eastern philosophy,

It's more impacted by chi,

Energy flow,

Chi.

So yeah,

Even the same symptom.

If you go to a Western science oriented doctor or Eastern medicine doctor,

Their approach is very,

Very different.

And then this kind of chi energy kind of holistic thing that nature and AI are connected,

Maybe is more embedded in that type of culture.

And of course,

Each culture has strengths and weaknesses.

But I mean,

To explain this confusion or a bit of backing off of forest bathing in the UK can be explained by the background understanding of how things are.

So Kirsten,

You've just heard Yasu talking about chi,

And I can see you rolling your eyes.

What makes you so uncomfortable about words like that?

I've only really ever heard terms like chi being mocked in comedy sketches.

So if we're if we're setting our stalls out now for the park bathe project,

I think is it fair to say that you are the hard skeptic?

Yeah,

That's pretty fair.

I have to say I'm converted.

I do think forest bathing is extremely valuable.

And there's a lot of research to show that including my own.

But I was previously highly skeptical of it as a idea.

Yeah,

I think on the balance of that,

I'm probably what I'd call a moderate skeptic,

Which I think is good for this project.

Because hopefully that makes us relate to the people that we've been encouraging to come to part bathe.

But there was another big misconception that we came across,

Wasn't there?

And that's that forest bathing is a really long walk.

And whilst forest bathing obviously capitalises on our deeply rooted human connections with trees and plants,

We're not running or climbing trees,

As Quing Li explains.

This is not exercise,

Or hiking or jogging.

It's simply being in nature,

Connecting with it through our sense of sight,

Hearing,

Taste,

Smell and touch.

Xingni,

Yoku or forest bathing is like a bridge by opening our senses.

It bridges the gap between us and natural world.

So forest bathing was being widely used in Japan way before it became a research area,

Which is really unusual,

Isn't it?

Yeah,

Absolutely.

I mean,

Usually you need to get the evidence first before anybody will invest in it and implement the idea.

The forest bathing became a science from feeding to a science.

It's a key word,

From feeding to a science.

And in terms of it being prescribed,

Can you just talk us through a bit more about how your GP in Japan would actually prescribe forest bathing to someone that comes to see them?

So in Japan,

They implemented forest bathing really because they had a stressed workforce.

So if you go to your GP in Japan,

And you've got high blood pressure or stress,

They'll say,

Well,

You can take this tablet or you can have a go at forest bathing.

And if you choose to have a go at forest bathing,

They have over 60 forest bathing centres set up in forests around Japan.

And there's usually a nurse and a doctor there.

And they'll measure your blood pressure at the start and end of your walk.

And they'll give you a map and send you off on a self-guided walk.

And then they look at how your blood pressure changes at the end.

And that's amazing,

Isn't it,

If you're a person going along to a forest bathing centre,

And you actually get to see how that walk in the woodland actually affects you.

I mean,

That gives you those objective results.

When I spoke with Queen Lee,

He talked a lot about stress and about stress being the root cause of so many illnesses.

In fact,

It was quite terrifying.

It was far more than I realised.

Stress is a key word to understand the background of forest bathing.

In Japan,

From 1980s,

Over 50 personal workers worked under higher stress levels due to the new technology.

Because of the technology stress,

From the new technology like computers,

Because why stress is a cure?

Because stress can induce many diseases such as cancers,

Hypertension,

Depression,

Cardiovascular diseases,

Stroke,

Gastric ulcer,

Obesity,

Alcoholism,

Panic disorder,

Eating disorder,

You name it.

So that's a terrifying shopping list of illnesses.

So I think to wrap our heads around forest bathing and how it impacts stress,

It might be really worth us looking at how stress affects the body and about our nervous system and how that operates.

Now Joanna Bristow Watkins is a forest bathing guide based in the southeast,

And she gives a pretty comprehensive explanation of that.

This is a really good description and a good example because Joanna acknowledges her own fight and flight system kicking in while she's talking to me.

We know that nature is good for us.

We know that it's something we look forward to as a child.

Even the dressing up,

You know,

To go out in the really cold weather at Christmas,

Walking off your Christmas meal and so on.

All of these things are associated with happy memories.

What we're really looking at is trying to get people's autonomic nervous system to move from one mode to the other.

So how I describe that in a session is I talk about how autonomic nervous system is obviously things we don't think about.

So we don't think about,

Oh,

I must digest my meal or I must fight that infection that I might have picked up yesterday.

You know,

These are all things that happen without us thinking about.

And it can be in two modes.

It can be in the sympathetic or the parasympathetic.

The sympathetic worded sounds like it's really good for us.

And 20% of the time it would be.

And that's the ideal 20% in that,

80% in the parasympathetic.

And it does have good aspects.

Things like now I'm probably in it a little bit because I'm being interviewed and I'm hoping that I'm presenting myself in a positive way.

So a little bit of nerves come up and that's one of the facets of the sympathetic.

But really its ancient purpose would have been to save us in the event of an emergency,

A short-term emergency.

When we needed all our wits about us,

We need to be able to run away from danger or stop and fight it.

To do that,

Blood needs to be diverted to the muscles,

Et cetera.

So the long and short of it is to survive in the short term,

Our body is wired to overwrite certain processes so that we can be more in our power in that moment.

And it does bypass things like sleep because obviously if we're being chased by a wild boar,

We don't want to fall asleep and we don't need to be digesting our dinner and fighting that minor infection in that survival moment.

So the problem we have is that today's life is very stressful and we're more 80% in that and 20% in the other,

The parasympathetic,

Which the rest of them recuperate.

So the thing with forest bathing is it is a trigger for moving you from one to the other.

That is the key to why it has this amazing impact on us.

The main trigger is the breath because the breath is the one thing that might be an autonomic facility that the body does,

But we can override it.

If we choose to take longer breaths,

We can.

And by taking those longer breaths and extending our out breath that little bit,

Even just to match the in breath to start with,

And then we look at extending it by a count of one or two,

Then you can see in people's eyes,

You can see them switching from one to the other.

And we know that they do because when we have our sharing,

People will say,

I actually stopped thinking about my problems.

So as we've just heard from Joanna,

Stress or extreme events can throw our nervous system off balance.

And we all know what that feels like.

But there's another system we can talk about here too.

That rather sneaky part of us that always has us on the go,

Waking up in the night to write to do lists,

Pushing us to be endlessly busy.

And this is our drive system.

And we've really developed with short term immediate stresses,

But we're now exposed to more chronic stress,

Like the bullying boss in the job that you need to pay your mortgage.

And we can also keep the threat going by replaying it even after the event has finished.

So anxiety and depression can be a main cause of cardiovascular illness,

Immune system illnesses and poor health and can lead to poor health choices because we often cope by comfort eating or drinking,

Which is all really scary and frighteningly close to home.

Queen Lee,

When he spoke to me explained how forest bathing can actually do a lot to help us.

Stress is not a new word.

Stress can produce a lot of what we call stress hormones,

Like adrenaline and non-agrenaline,

Also called stress.

So adrenaline is a mental stress hormone.

So can produce a lot of mental disorders like depression.

After I conducted the 20 years experiment,

I have found forest bathing can reduce stress.

I love one of Queen Lee's early studies from,

I think 2006.

It saw him take a group of 12 businessmen from Tokyo to a hotel in Iyama City for a forest bathing trip to measure the effects trees and being in the forest had upon their stress levels.

Queen Lee measured their cortisol levels,

Which is secreted when we get stressed,

Like when your boss keeps loading work on you.

Our cortisol levels normally regulate themselves,

But they can get dysregulated.

So Kirsten,

Could you pick up here and explain exactly what cortisol is and how it affects our body's health?

So neurohormones like cortisol and adrenaline,

Those are secreted around the body when we experience some kind of threat.

So the tiger jumping at us out of a bush and they really are a way of the body trying to preserve its self and keep itself safe.

They put us on alert and they get us ready to fight or flight.

So to run away or to take some other form of defensive action.

But unfortunately in modern day life,

We can encounter a lot of chronic stressors and the stress is ongoing and we weren't designed to deal with that.

We were designed to deal with media threats like the tiger,

Not the boss.

So unfortunately we have a really good way of keeping that cortisol circulating around our bodies,

Which is really bad for our mood and for our health in terms of suppressing our immune system and putting our cardiovascular system on high alert.

But the good news is that Queenly has found that when we're in nature,

Our cortisol levels drop and all of those negative effects of stress start to reverse,

Which means our heart rate slows and our digestion works efficiently.

We feel calmer.

We have increased energy.

We feel less depressed and less anxious.

And of course,

What does that mean?

We sleep better.

Queenly showed that trees help suppress that fight or flight response,

That system that gets stuck on high alert.

So this is all really good news and even more reason why people should maybe consider having a go at forest bathing,

Isn't it?

Yeah.

If you think of all the benefits that forest bathing can offer,

It's something we should all be doing and something we can all benefit from.

Actually,

For me,

The thing that I hear in that is the sleep.

I saw in Japan that some studies have shown that 30 to 40% of the population struggles with sleep and 40% say they sleep less than six hours a night when I think doctors as a standard tend to recommend seven to nine hours.

And a British study has shown that 36% of British adults have poor sleep.

So we know that sleep is at the root of good health.

It helps balance our hormones.

It helps our brains function.

It keeps that brain fog away.

It keeps our immune system working like it should do.

But poor sleep is actually linked to another horrible,

Scary shopping list of illnesses,

Isn't it?

Such as increased heart disease,

Kidney disease,

High blood pressure,

Diabetes,

Oh my God,

And stroke.

So we know that not getting enough sleep makes us grumpy and irritable,

But actually it makes us really ill,

Doesn't it?

Yeah,

Sleep's definitely a crucial one and I personally know a lot of people who struggle with sleep,

Including myself,

And I've had quite a lot of feedback that people sleep better after forest bathing.

In Quing Lee's study,

After taking two hour walks twice a day in forests covering five kilometres,

He measured the businessmen's body movement by a device on their wrists that showed how much they slept before,

During and after the trip.

Before the trip,

They had an average sleep time of six and a half hours,

Which went up to seven and a half hours during the trip and just under seven hours afterwards.

So a good reason for spending time forest bathing.

Absolutely.

I mean,

Even if you could just increase your nightly sleep by,

You know,

45 minutes,

It just accumulates and makes a difference.

So I think we're establishing that there's a lot more happening underneath the surface that we don't know about.

And this is a nice lead on to something that when I came across this term,

I thought sounded like it was from a sci-fi movie.

And this is the natural killer cells that we have within our bodies.

These are white blood cells that basically go to war on anything that is causing problems within our body.

And Quing Lee explains a little bit about what they do.

In our body,

Immune system is very important because the immune system can kill the tumour cells,

Can kill the virus,

Including the COVID-19,

Also can kill bacteria.

The immune system,

We call the natural killer cell.

It's the first defense line for our health.

So in fact,

Natural killer cell kill tumour cell or virus by release three kinds of anti-cancer proteins preferring grad times and granulation.

So MKCO can kill the cells infected by virus.

So natural killer cells are a real thing.

And actually it's something that we really should know about.

Kirsten,

Can you explain a little bit more about what these groovy cells do in our body?

Yeah.

So these natural killer cells are a type of white blood cell,

And they've been shown to increase after forest bathing.

They can attack and kill cells that contain viruses or tumours.

And they do so with the help of anti-cancer proteins,

Which drill a hole in the cell and kill them.

And a higher MK cell count and activity is associated with lower rates of cancer.

Which again is food for thought.

And I love the idea of these cells drilling holes.

This is where I've got the whole sci-fi movie thing in my head.

But I kind of like the idea that I've got this little army of natural killer cells,

You know,

Marching around my body,

Taking out anything that looks remotely like cancer or something nasty that I don't want.

When we know all this research and when you start to understand it and get beneath the surface,

It really does make you practice what you preach.

And both Kirsten and I do do that.

Not because we want to be right and be able to tell people,

But because it helps.

I walk with my daughter three times a week to school,

And we spend an hour walking through the park.

And whilst she won't formally do forest bathing with me,

I'm constantly pointing out leaves and the water and how still it is,

Or a squirrel running past.

And we quite often kick the leaves together and we'll stop and notice something.

This morning it was the fog.

And so we get that wonderful time together,

So we get the social connection,

But we also get,

Not necessarily the slowness,

But we get the nature connection.

And then when I've dropped her off,

I then kick in the slowness of forest bathing.

And I will do a route that's off the beaten track and I will go and drift past trees in quite a floaty way.

And I kind of feel like I get my little forest bathing fix.

And I also do two additional walks in the week in the park with two girlfriends.

And they're my guinea pigs,

So I'm always trying out new forest bathing exercises on them.

And they've found themselves adopting these themselves,

So it's really easy to do and to incorporate into your life.

And actually once you do it and you just feel so lovely and floaty when you leave the park that it's easy to continue with.

But Kirsten,

You're a forest bathing guide.

Tell us how you practice what you preach.

Well,

Aside from taking people out on forest bathing walks,

Which I also get a lot of benefit from as well,

Even though I'm guiding them,

I'll make sure I get out into nature every day.

So often I'll start my morning with a run,

But I've started to incorporate five or 10 minutes of forest bathing in the middle of my run.

So when I get to the woodland,

I slow down and really notice my surroundings and I might just stand still and look at the view for a while and then I'll carry on running.

So that's how I've really brought it into every day.

I also try to take a break after lunch at work because everybody feels tired after they've just had their lunch.

So I'm generally not very productive and I need to wake up,

So I'll go outside.

And even if it just means walking around the communal gardens where I live and just noticing the different flowers that have come out or the different colours of the leaves,

I find that's really helpful for just sort of refreshing me and waking me up.

And when I go back to my desk,

I'm often a lot more productive.

I know when we have our participants on park bathe,

We tell them just do five minutes here,

There and everywhere.

And I sometimes see people kind of nodding and going,

Yeah,

Yeah,

And thinking that wouldn't do anything.

But the really weird thing is it does because what I find is it accumulates.

So if you do a longer burst later in the day,

Because I'm attuned and I've been sort of conditioned,

I suppose,

By that morning exposure to nature,

If I walk down the road or do something outside,

Even for five minutes,

It's like something automatic happens and my autopilot button just switches off and I suddenly ping into this awareness mode where I do notice if there's a berry,

You know,

Randomly in November still on a bush.

Or I noticed something today which was one leaf on a tree.

It was like the last leaf standing and it was still green and it was hanging on and all of its friends had died and dropped off.

You know,

I passed it for no more than 10 or 15 seconds.

But me and that leaf,

We just had a moment where I was going,

You go leaf,

You stay,

You hang on.

And that left me with a little smile and one of those just little micro moments,

A little leap of joy.

And by joining all those experiences together,

Even if it is just micro moments,

It really has a lasting effect.

Yeah,

It definitely has cumulative effect.

So the more attuned you become,

The more you just start to notice all those small details in your surroundings that we would have previously missed.

Yeah,

So if anything else,

We are adverts for forest bathing.

As part of the series,

I also had the pleasure to interview Dr.

Miyazaki,

Who Kirsten also mentioned earlier.

He lives in Japan.

And so I had some fun and games connecting with him and his translator on Zoom,

Which had us giggling quite a few times,

But we got there in the end.

Okay.

And through his translator,

He explained a little bit more about why we feel better when we go outdoors.

And like Kirsten and I do,

We just take those little micro moments,

Noticing nature.

Since a human has lived in the nature environment for several million years,

We are made for nature,

Including our genes.

If we are in a typical nature,

Like forests or parks,

We feel automatically comfortable without knowing.

Dr.

Miyazaki had quite a different upbringing to Quingly,

Who was brought up in the city,

As Dr.

Miyazaki enjoyed nature from a young age.

I liked nature when I was very young age,

When I was kindergarten.

From the early childhood,

When I touch the plants or go into the forest,

I feel really relaxed.

When I become adult,

I thought it would be very useful to research about this.

I define that humans and forests become unified or become synchronized so their stress is reduced.

When humans and the environment are synchronized,

The comfort feeling is enhanced.

This is the principle of comfort that can be applied to everything from hobbies to music concerts.

Much of his work centres around what we feel as comfortable and when we are feeling in a place that we are content and at ease.

But maybe Kirsten,

You can talk a little bit about what Dr.

Miyazaki says about this.

I've heard Dr.

Miyazaki talk about this as well.

I think what he means is that we are all different,

We all have different backgrounds.

In terms of being comfortable in nature,

We often go for what is familiar.

For some people,

They might enjoy going out into a large wooded area and spending time alone.

But then for other people,

They might get their nature connection more simply just through stepping out onto their balcony and tending to their pot plants there or noticing their plants or looking at the view.

So really I think what he's talking about there is that we all have different ways of connecting to nature and we'll all have our own different way of bringing it into our daily lives.

And I think that's really key and he talks about this later in our interview that nature is individual and in fact his research has shown if you don't interact with nature on your terms or in a way that suits you,

You have less wellbeing results.

Which kind of makes sense.

It's interesting to think that if you're on a forest bathing walk and you're following an exercise and it just doesn't chime,

This is why it's really important that you say what you say at the beginning,

Which is do what makes you feel comfortable.

If you're really engaging with a hearing element,

So you've just heard birdsong or someone's just trodden on a twig and it made a really great cracking noise and not following maybe a visual exercise that you're being directed to do,

Then that's exactly as I understand what Dr.

Miyazaki is talking about.

He says go with your instinct,

Go with where your attention is and where the enjoyment is because then you're going to get that benefit rather than being directed to do something that maybe doesn't feel comfortable,

Doesn't feel quite right.

I think Dr.

Miyazaki's research is absolutely fascinating because of this idea that he brings the forest into his lab in this climate controlled room.

Now as I understand this was built to control the atmosphere,

The temperature and the sensory stimulus that he was testing.

So in this way he could separate out the senses and focus on touch or smell or vision as separate entities without other variables like whether it rained during the study outside in the forest or if it was cold or if a deer startled half of the participants during the study.

So his participants would just simply look sitting inside this controlled room at a picture of a forest or they might touch a piece of raw Hinoki cedar wood and then Dr.

Miyazaki would measure their responses.

And what was really staggering was that his research showed that the participants responded to a piece of untreated cedar wood in the same way in the lab as they would have done had they been outside in the forest.

Interesting is that even we go to the forest or even we are in the room and just contact the nature,

The result is same.

And he did a control with this which I thought was really interesting.

He had participants touch heated and treated wood inside the controlled room and the results dropped.

Those wellbeing results were not the same so it had to be the raw untreated wood for those people to get the wellbeing benefits.

So obviously this room has allowed his research team a much more nuanced and personalised approach to the effects nature has upon us and not just on our wellbeing but us as individuals.

Another good reason why Miyazaki had this climate controlled lab is because you can take really complex physiological measurements in a lab with equipment that involves lots of wires and caps and you just wouldn't be able to wear that kind of equipment and go for a walk around the woods because you'd pull all the wires out.

And also if nature feels unattainable or a long way away,

Either mentally or physically,

That actually looking at a picture of a forest has a boost to the immune system and a boost to mood.

You know you can do that by looking out your window.

We can access nature in pictorial forms really really easily and likewise we can bring essential oils and the essence of trees into the home really really easily as well.

So I think this is really positive research for making nature so much more accessible than we perhaps realised it might be.

I love how he separated out the senses as well.

Yes.

And that's something that me and Yasu tried to do with our previous research.

We asked people which senses they were using the most to connect with nature and it tended to be visual listening and then smell but we also measured people's heart rate variability during those different sensory activities and were able to see where heart rate variability went up the most and it was often during listening and in particular listening to the sound of running water you've got a huge heart rate variability increase.

Even if you just imagine that,

You know even just as you said running water,

I went to beautiful waterfall,

I could picture it in my mind and I could just hear it because I know what it sounds like and this is the way that you know our minds are so incredible and infinite and yet also a bit stupid because it doesn't know the difference between the past and the present so my mind jumps onto that waterfall image and the sound and I get just a little micro ooh it's nice and so I know that feeling because I've just felt it and this is what all of this research taps into which I think is just so clever how we're capitalising on what the mind does in that it holds onto memories and then we can evoke hopefully those good feelings and bring them into a moment perhaps where we need it most.

Yeah,

Human imagination is incredibly powerful.

I mean it's easy enough to replay threatening events and upset ourselves so why shouldn't it be easy to remember something nice like a waterfall and improve our mood as well?

Yeah and I think sometimes it's just knowing this stuff.

We couldn't talk about the science of forest bathing without giving time to phytoncides so Kirsten,

What on earth are they?

Well they sound a bit science fiction as well don't they,

Phytoncides.

If we break down that term phytoncide,

Phyton is Greek for plant and side is to kill but they're essentially wood essential oils so the trees don't just give out oxygen that we breathe in,

They also give out these volatile organic compounds called phytoncides and when we breathe these in we get a huge immune boost as well as improved mood and heart health and Dr Quing Lee has done quite a lot of research on phytoncides so in one study he diffused phytoncides into a hotel room over three nights and found that not only did it improve mood and sleep quality but it also increased those natural killer cells so those white blood cells we talked about earlier and the anti-cancer proteins and it also reduced stress hormones and reduced people's experience of stress.

Yeah it does sound like it's from a sci-fi movie,

You're totally right.

So I think phytoncides are just so fascinating and I'd always thought that aromatherapy was woo woo and you know I like the smells of oils but I never really thought that they were doing anything good for me but actually what's really interesting,

You can really get into aromatherapy oils because the concentration of the oils varies depending on temperature and also time of year if you're walking around a forest there's going to be more oils when it's warmer and also there's more chemicals in the air after it's rained and they also vary from tree to tree but in the UK if we're looking at what phytoncides are out there to help us we have essential oils from the pine trees,

Cedar and spruces.

In Japan the essential oil that's used in a lot of the studies is Hinoki Cyprus oil.

Hinoki is known for its beneficial properties to humans because phytoncides contain terpenes and that's actually what you smell when you're forest bathing and some of these terpenes smell like lemons.

Alpha-pinene is one of the most common and smells of yes,

It smells of pine.

Beta-pinene smells more like herbs,

I was quite fascinated it smells actually a bit like basil or dill and camphine which almost smells like disinfectant.

Several of our part-bathers would when we're doing the smelling exercises often say that something smells of disinfectant.

Yeah that's definitely something we found a lot of our participants were really surprised by how much they could smell and the range of smells that they were getting when they were crushing the leaves.

Quite a few people would say oh this smells like tea bags or this smells like licorice so there's quite a range of subtle smells out there that we only really get if we really get in amongst those smells and try and pick them up and exposure to natural oils is already known to lift mood but there are researchers who've taken this a step further.

For example some researchers found that phytoncides improved mood more than antidepressants could.

Which I just think is absolutely staggering.

I've had to completely reverse my opinion of aromatherapy and I take my hat off now to these oils because this is such a simple and easy thing that we can bring into the home and it doesn't even have to be that expensive because if you diffuse them in oil or water they last a long time.

This is why at the end of this episode we will be giving you tips on how to make your own reed diffuser and bring those oils into your home and get the benefits from them inside your kitchen or your office or your bedroom.

But even though I'm a complete convert to essential oils one of the things I have found reading research is that scientists don't know everything.

They don't know the answer to everything and this is an ongoing area of research and I think that's what makes it so exciting.

In fact Dr.

Miyazaki when he was measuring cortisol he found that contact with nature made them drop but he also found that by using brain recording equipment that activity in the prefrontal cortex reduces but he has absolutely no idea why.

By contacting nature the prefrontal cortex activity is reduced.

So why is this important?

I'm going to explain why it happens.

Yeah I read that paper as well and there was no explanation about whether this was a good or a bad thing.

And sometimes it's not.

Sometimes it just is.

You know it will provoke more research in that area.

Of course the studies that Queen Lee and Dr.

Miyazaki did were all based in Japan but the people from Crystal Palace and all our neighbouring surroundings have also been involved with a scientific experiment as part of Parkbathe.

Each participant filled in a well-being survey before and after their walk so we could see if forest bathing made any difference to how they felt.

They also wore heart rate variability straps.

These are little chest straps that fit on underneath their shirt and after a while people didn't even notice they were wearing them.

Kirsten perhaps you could just quickly explain why we did that.

So heart rate variability is an indication of how well balanced our fight,

Flight or sympathetic nervous system is with our rest and digest or parasympathetic nervous system.

So a healthy heart doesn't beat like a second hand on a clock.

It doesn't beat with that regularity.

There's a bit of variation in there and the more variable the beats are the more balanced our sympathetic and parasympathetic nervous system are so the better our heart rate variability is.

And heart rate variability indicates that we're feeling more relaxed and it's also an indicator of better heart health.

That's really good data for you to collect.

Absolutely because if you can show that something like spending an hour in woodland can have an effect on our physiology,

So how our body responds to being in nature,

Then that's really compelling evidence to take to people like the NHS to persuade them to make this more available to a wider audience.

So I feel like there should be a drum roll here.

This is so super exciting having spent months walking around the park leading people.

Kirsten can you share what results you have got from your research?

So our adults who came on the park bath walks experienced an average of 15% increase in heart rate variability.

Now that is huge.

That indicates they're feeling more relaxed,

Their heart health has improved and if you took that data to a health professional they would be really pleased with the size of improvement there.

15% is massive.

This is radio so we can't see this but Kirsten is grinning.

And then with the questionnaire data we saw a 39% increase in how connected people felt to nature,

A 27% increase in how connected they felt to each other,

So an improvement in social connection,

A massive 51% reduction in mind chatter,

So ruminating and going over problems or going through your to-do list.

That reduced by 51%.

We had a 40% reduction in anxiety.

Again that is huge,

Really pleased with that.

And we had a 41% reduction in how sceptical people felt about forest bathing or the park bath project.

Are you happy with those results?

It's amazing.

I mean the magnitude of changes is fantastic.

In a previous UK study where we spent two hours in ancient woodland we got similar results actually but these in some ways these are a lot better because people have only had one hour in a city park.

And I wonder if the profound change that we're seeing here is partly the realisation that you don't have to go far,

This is something that you can do on your doorstep and you can access and practice every day.

I think that really took a lot of people by surprise.

I think you're right.

So it's absolutely amazing that the data actually reflects what we saw because we saw these changes didn't we?

Yeah and our volunteers who have been on all of our walks with us said that after 20 minutes they could see the change,

They could see people really slow down,

Relax and get into the noticing of their surroundings.

And that they noticed as well that the group seems a lot calmer but also more connected to each other.

Yeah,

We've had participants afterwards sharing phone numbers,

They've walked away together,

They've crossed the park back to the station,

People have stayed and chatted for up to an hour,

There was a definite visible connection which was wonderful to be part of.

So these results are really encouraging,

We're not going to give this up.

We're going to keep going revisiting Crystal Palace Park and maybe even some other parks with this model that I think we can safely say works.

We are the only team that have been doing forest bathing in urban parks.

Quin Li has also run forest bathing studies in Tokyo Parks and in fact his guinea pigs were his students.

I also studied the effect of forest bathing in the city parks in Tokyo.

I took my students,

In fact I have conducted about 10 experiments and I thought that forest bathing in the city parks in Tokyo also can reduce the negative feelings such as anxiety,

Depression,

Anger,

Fatigue,

Confusion,

But increase your positive emotion like vigour.

Dr Li makes a really important point of why we would encourage people to try forest bathing in an urban park.

What he notices is that his participants had improved vigour which is energy.

The benefits last long,

Way beyond when you leave the park gates.

We know that this is true because we had an email from a park bathe participant who told us that even eight hours later she was still floating around her kitchen after the session she'd done with us that morning.

I told Dr Li about our park bathe results and actually he was quite impressed.

Park bathe is very similar to my experiment.

Increase in the heart rate variability and increase the positive feeling and reduce the negative feeling like anxiety.

It's good.

So I think I said at the beginning of all of this that the science speaks for itself and really it does.

Forest bathing might sound wishy-washy but the results are most definitely not.

But if you're still not convinced about getting out into your local park you can bring the park to you.

Kirsten and I have put together some really easy ways to get the benefits of essential wood oils into your home.

But actually it goes even further than that but we can also put plants into our home and I was fascinated to read that NASA did a clean air study where they looked at which plants were the best to have in your home.

And actually I've got a little list here.

The top plants for oxygen supply are a peace lily,

Mother-in-law's tongue,

Ivy,

Golden pothos,

Chrysanthemum,

Gerbra daisy,

My personal favourite,

Azalea,

Oh I quite like an azalea too,

Or a bamboo palm.

So plenty of choice there.

I think spider plants are also pretty good for oxygen supply as well.

So Kirsten if we want to get those essential oils into our home how do we do that?

One of the ways you can bring wood essential oils into the home is to use a diffuser.

There are ceramic ones available or you can get the ones that you plug in and they pump out a vapour containing the wood essential oils.

I use cedarwood and pinewood at home.

Or you can have chips of cedar bark and scatter those around the home.

In fact they're also meant to be quite good for keeping clothes moths at bay.

These are great tips and actually I have Hinoki oil right next to my desk but also when I spoke to Quinn Lee he had a great big chunk of Hinoki wood right next to his desk.

In fact he had two and he picked them up and he waved them in front of the zoom camera which I thought was really funny.

So he practices what he preaches too.

So there's lots of different ways.

We've also got a top tip on how to make your own reed diffuser which might be just a nice present to give to someone else.

So that's going to be available as a separate recording.

If you've enjoyed what we've shared today please do hit subscribe and share the episode with friends and family who'd like to listen.

As always we'd love to hear from you so do contact us on social media or you can drop us an email.

Join us next time because we will be geeking out on trees.

We will be giving you fun facts,

So much information and everything you could possibly want to know about our wonderful tall friends.

So see you then.