'Welcome to Chasing Life. As you probably know, Earth Day is next week, and every year when April comes around, it does get me thinking about just how intricately our health is tied to our nature, our climate. I really have enjoyed covering this topic on the show over the years because I've learned so many fascinating things. I've learnt so much compelling science that helps explain and even quantify our relationship with the environment. For instance, you know that calming effect you get at the beach. You know that, but it turns out there are proven psychological benefits to just being near big bodies of water. And on the flip side, there's now plenty of data that tells us that things like mood disorders, mental illness, insomnia, even gun violence and aggression, all of those can be exacerbated by extreme heat, which we know is becoming more common as our climate changes. When I think back to all these conversations I've had over the years, they've enforced an idea to me that nature does truly give and take. It can be one of our greatest sources for healing and it can challenge us as well in unexpected ways. So today I thought it would be good to dig into the Chasing Life archives and share two of my favorite conversations that tackle this idea. The first is about the health benefits of just spending time outdoors. What do we really know about that? How do we quantify that? And later, a psychologist is going to talk about the pervasive threat, but also the silver lining of climate anxiety. I'm Dr. Sanjay Gupta, CNN's chief medical correspondent, and this is Chasing Life. Our first guest is Dr. Melissa Lem, one of the first doctors in Canada to start prescribing time in nature to her patients. She gives prescriptions for people to be outside. This wasn't some knee-jerk or gut-instinct decision. She says the practice is based on a mountain of evidence. We first talked back in spring of 2022.

'There was this 2018 meta-analysis that looked at a wide variety of different health conditions from diabetes to hypertension, to birth outcomes, ADHD in children, eyesight in kids. And it found that almost across the board, these studies showed some benefit when people spent more time outside. So in general, the trend says that nature is good for our bodies and brains. And it's backed up by lab studies, right? Where they're looking at body hormones and neurotransmitters. They're looking at blood pressure and heart variability response. When people spend time sitting in or looking at nature scenes versus urban scenes, these markers respond in a positive way.

I mean, if you had your ideal patient visit, anything you could do, like what would it look like?

Oh, my gosh. I mean, it would be probably in the middle of a forest somewhere, right, either either outside with open air or in a clinic, you know, with glass walls. So we could be looking at the woods because we know there's a lot of research showing that when people spend time even looking at nature or spending time in nature, they calm down and they become more pro social. They become more more open. So I think that would be wonderful if I had a clinic in the Middle of the forest. You know with my ophthalmoscope and my you know my thermometer and everything on the wall of a wooden cabin or something seeing patients in the woods I would love that.

I totally agree with you. I mean, I think it's, as you say, maybe not realistic. But how we think about medicine, how we think about healing, I think is important, you know, for physicians to be thinking along those lines. I mean I think we're so used to saying, okay, someone's hypertensive, what's the first thing we're going to do? You know, prescribe a medication. And the idea of nature as a therapeutic is again at once both really logical and yet revelatory in some way as well. What do you think is happening, Doc, with someone who is sitting in nature or even staring at nature? Is this a physiological thing? What do think's happening?

'Well, there are a couple of psychological theories about why nature is so good for our brains. And the first one is attention restoration theory. And essentially when we spend time in these busy urban environments with all the hard edges and lights and traffic and crowds, this tires out our powers of conscious attention and this increases fatigue and irritability. Whereas when we spent time in nature, it's this source of soft fascination. So it's interesting, but it doesn't make us constantly have to focus to navigate our way around different obstacles. And that restores our powers of attention and reduces that fatigue and irritability. There's a second theory called stress reduction theory, which says that when you spend time in a stressful environment, then spending time in nature actually allows you to recover faster. And this goes back to evolutionary thinking. Early humans who spent time in biodiverse environments, they had everything that they needed to survive. So they had sources of food, shelter, water. And so these brains kind of grew to... Want to spend time in these natural environments that were good for their survival. And they've really passed these nature-loving genes down to future generations like us. So it's really hardwired into us from an evolutionary sense as well.

Maybe, you know, that goes without saying, but just being outside, it is almost, that is how human beings were designed. We went inside for shelter, but that wasn't where we were supposed to spend most of our time. We were supposed spend most our time in nature, on earth, interacting in a symbiotic way with everything else that's living on this planet. I just find that really logical and it fits. Do we have any insights into what is specifically happening in areas of the brain? When they're exposed to nature?

And so scientists have used this MRI technology to figure out how blood flow changes in the brain when you're exposed to different stimuli, whether they're rural or urban. So there was this recent study from Korea where they showed participants either rural photos like mountains and forest, or urban built scenes for two minutes. And then they put them in this functional MRI. And what they showed was that when they saw these photos of urban scenes, blood flow and brain activity increased in the amygdala or the area of the brain that can sometimes be linked to impulsivity and anxiety. But the nature scenes actually increased activity in the anterior cingulate and insula, which are both linked to increased empathy and altruism. So calm and optimism and love, these all seem to be triggered when we even just look at photos of nature, but the impulsively and anxiety increases with urban scenes.

'You know, this reminded me of an experience I had in Japan a while back before the pandemic. I tried something called shinrin-yoku, also known as forest bathing. Now, don't get the wrong idea. I didn't take my clothes off or even get wet. Instead, I just immersed myself in the atmosphere of the forest. It was a cold January day, I remember, just outside Tokyo. We were hiking through the forest, breathing in the crisp winter air. And I felt calmer. My heartbeat slowed. I was at peace. When I was done, I filled out a questionnaire and had some of my vitals checked, and both my cortisol and my blood pressure had dropped significantly. I asked Dr. Lem to explain the science behind this.

I did take some time to experience a forest therapy session actually during the pandemic. I was a little skeptical about it because usually when I'm on a trail, I'm going, I'm running or I'm hiking fast. And so the thought of slowing down and connecting was a bit foreign to me, but it was amazing to me actually how easy it was to slip into that state of noticing my environment and slowing down from the little drops of water falling off the leaves to an ant crawling up the tree. I found that experience actually made me feel calmer and more connected than when I go for a hike, actually, and I'd really encourage people to do that. If they do tend to pound the pavement or pound the trail, you know, to actually take time to slow down and look and smell and feel.

'You know, I remember when I did this experience in Japan, they made a big point about something known as phytoncides, these natural stress-busting chemicals, I guess. And we humans also have receptors for some of these phytoncides as well. So when we're breathing in the aroma of the forest, we may be breathing in phytoncide and could be helping boost immunity, bust stress, you know, a variety of things. Is that real? What do you think's happening?

Yeah, so there has been research done on phytoncides looking at immune responses. And I think some of the most famous studies look at levels of your natural killer cells and immunoproteins before nature experiences and after. And what they found was that whether it's in a hotel room, where you're just smelling the phytoincides for three nights, or even on a real trail, you know, where they measure the concentration of phytencides in the air, they found that those natural killer cells which fight off viruses and bacteria and immuno proteins increase. And sometimes can stay boosted for as long as a month afterwards. You know what's interesting, I think, though, about phytoncides is they're meant to fight off fungi and insects, but for humans, when we smell it, when we take in the smell of nature, it does seem to be good for us.

How could you not want to preserve this when you hear all this, right? I mean, I remember playing a lot outdoors when I was a kid, breathing in the aroma of the trees and everything around me. But it's different for kids these days. I mean are we seeing a difference? Are we seeing an impact on the health of younger people because they're indoors more often?

I think we absolutely are. So there's this crisis of too much screen time and not enough green time, right? There was a book by author Richard Louv from the Us called The Last Child in the Woods, and he coined this term nature deficit disorder. So as you and I know, it's not an official medical diagnosis, but it really describes all of the different problems that can happen when we're not spending enough time outside. Kids are more near sighted because they're staring at screens and not looking into the distance like they used to. Kids are having increased rates of obesity. Even high blood pressure and diabetes we're seeing at younger ages and kids who are sedentary and not spending enough time outdoors where we're most healthy.

Dr. Lem founded Parks Prescriptions in 2020 to try to get more people outside. It's the first national nature prescription program in Canada, and I have to say, it's a pretty exciting concept. We do have something similar here in the United States called Park RX America. In Canada, licensed healthcare professionals who register with Parks Prescription can now prescribe a Canadian National Parks visitor pass to their patients.

And I think that's important because often as physicians will hand someone a prescription or will say, go do this thing, but it can be hard for them to do that thing, right? Like it can hard for to access nature. So I think in a real way, giving them a pass that makes it free for them to go to national park or a national historic site or marine conservation area, really allows them to access more easily.

Can you talk me through how it might work if, let's say, I were a patient and I were to come to you, what sorts of things, first of all, might warrant a Parks prescription and how do you go about prescribing it?

'Well, nature is good for such a wide variety of conditions that it could almost be prescribed for anything. So that's not really limiting in that sense. But I would say that the types of patients I most typically prescribe nature to are adults with mental health concerns. And so if the person happens to not be spending much time outdoors, I would talk to them about the evidence behind it. And so we have a standard recommendation that patients spend at least two hours in nature each week and at least 20 minutes each time. And that's backed up by research as well. And then we work in a patient-centered way to figure out how to incorporate nature into their everyday lives. So figure out what green spaces are nearby. Can you walk or bike through a greenway instead of taking the car? We just really work to make sure that it's something that they can do and then follow up after that.

That is interesting. You do have a specific dosage, if you will. Two hours and a stroll through your neighborhood with trees, does that count?

'Do you know what's really interesting in some of these studies is that nature has been self-defined. So if you feel like you've had a meaningful experience in nature, you can get those health benefits. So if we can change our minds to think that we're having a nature experience in our neighborhood park, or even in our garden, in our backyard, we can reap those benefits, it seems.

So there you have it. Get outside for at least two hours a week. You can do it, doctor's orders. When we come back, we're gonna talk about how to manage the emotional toll of a changing climate that is changing the nature that we love. Stick with us. So long time listeners will know that I have three girls, three teenage girls, and you've likely heard me talk about the challenges of raising kids in a world full of threats that I frankly did not face. Two wars, social media, pandemic, and the ever present threat of climate change. So our next conversation is with Britt Ray, a Stanford researcher, an expert on the mental health effects of climate change and author of quote, Generation Dread. Finding purpose in an age of climate crisis. When we spoke in the summer of 2022, she helped me make sense of existential dread as a person and as a parent. What is climate anxiety? How do you describe that to someone?

Climate anxiety is really an umbrella term for a variety of challenging emotions that a person can experience when confronting the climate crisis. And anxiety, of course, is one of these emotions that people often report, but it also includes things like grief about what's being lost, fear, of, course, worry, anger.

How prevalent do you think this is?

In a study that my colleagues and I did of 10,000 young people in 10 countries around the world, India, Nigeria, the Philippines, Brazil, UK, US, Finland, and some others. And what we learned was that 45% of these global respondents told us that their feelings about the climate crisis are disrupting their ability to function.

Wow. You know, they have every right to be anxious, right? And my middle daughter was this daughter who she would always talk about, this is what I wanna do when I grow up. I'm gonna be an architect. I'm going to marry, get married at such and such age. I want to have this number of kids and blah, blah, And one day at dinner a few years ago, we're sitting there talking. And I said, so Sky, that's her name, Sky, how are the plans going for the rest of your life? Nah, it's not happening anymore, she said. So why not? Well, it was not that long after the climate change report had come out, and her interpretation and the interpretation that she was hearing in school was kind of like, what difference does it make? We're not really going to be inhabiting a world that is worth that inhabiting. And I tell you, Britt, I was a little bit stymied there. What do I say? She's not wrong. What would you tell her? I mean, what do you say? How do you balance that hope and honesty?

Thank you for that poignant picture of how this emerges in our lives and in our relationships and how difficult it is. I think you're absolutely right to not invalidate the anxiety. It comes from a very rational appraisal of what's going on. And so what requires flexible thinking is this ability to balance hope and fear. And sit in the gray zone of uncertainty productively so that we can face the future with an openness towards both how daunting and scary what we're moving towards is, while also knowing that there is so much to be done that can make a difference. We are not in a unidirectional losing game. There are small wins along the way that people are already making and that we can all be a part of increasingly making. And so getting beyond this black and white thinking is really key. So that requires sitting on the fence rather than associating with either side of it, which is not where an anxious brain easily takes you. And which is why emotional processing and coping skills are really important to help people see all is not lost, even though it's bad.

We evolved to be able to deal with threats, but immediate threats. And now if it's not going to interfere with dinner plans tonight, we don't seem to pay as much attention to it and climate change is because I think it feels distant for so many people. They sort of put it off and maybe that's, that's the human brain.

'I do find it odd and strange and inexcusable, for example, across the American public, let's say right now, for people to still think of it as a distant or far away phenomenon, considering how many wildfires and floods and hurricanes, drought, American soil experiences. The philosopher Timothy Morton talks about the climate crisis as a hyperobject. And hyperobjects are things that are so vast and all-encompassing that you can't see their edges. It's not clear where the borders or boundaries are. Climate change, for example, shows up in what comes out of our tailpipe after burning fossil fuels and having air pollution. It shows up in news reports about declining fisheries. And it shows up Anxious parents' conversations about what their kids are going to have to deal with on a warming planet and so on and so forth. It just is really difficult to then identify where can I intervene when it touches everything and it is enmeshed in really complex systems. And so that hyper-object-ness means that we can't think about it very clearly. And when you can't think about it very clearly. It's easier to really not regard it or think about it at all in many cases.

'You know, my daughter again, Sky, we took a lot of walks during the pandemic because that's something we could do pretty easily. And she would ask me on a particularly nice day when we're outside and you hear birds chirping and you're looking at these beautiful green trees and you just smell that aroma of the forest. She would ask if I thought that her grandkids would get to be able to do the same thing one day or not. And again, you know, I... I mean, you want to say the thing that's going to be aswaging of the anxiety. Yes, of course, they'll be able to do this, you know, they're going to hear birds in the trees and all that. And it's hard because at the same time, we hear that emissions have to peak essentially by 2025. If we want to keep global warming to one and a half degrees Celsius, it's sort of a now or never proposition that people are hearing that she's hearing that I'm hearing. So. The hyper-object seems to get more definition around it, if you start to put a time frame on that. Is that a good framing, you know, in this context of climate anxiety?

'In moments of civilizational threat in world wars, we do not rally and take action by responding to calming messages that try to assuage our fears and tell us that things are relatively fine and that we can just make a few changes here and there in order to not be killed or what have you. The rhetorical power of fear and threat is crucial to mobilizing the masses at the scales required in order to protect one's society, civilization. When it's time-bound, we require that type of mustering force to get our ducks in a row to organize us. It will raise anxieties naturally because it's commensurate with what the science is telling us, that we have these alarming messages about what needs to be done. This requires a lot of courage and coping skills along the way so that the anxiety doesn't rob you of your functioning. So there's a lot that people can do to support themselves as they take on this uncomfortable information and use it to muster the will to use that. That time frame most effectively.

Yeah, you know, I think it's really interesting to see sometimes what resonates with people and sometimes it's surprising. It's interesting. You are a mom now. Congratulations.

Thank you.

I know you thought a lot about that decision, whether or not you wanted to have a child given the climate crisis, and I'm just wondering if you're comfortable telling me a little bit about that decision and how you work through it.

It was a few years of thinking, reading, talking, interviewing, gathering really diverse perspectives on what it means to live amidst consecutive threat scenarios and what it means to be resilient under existential threat, which many humans have been experiencing for time immemorial. And ultimately, the decision to have a child meant for me that I have to be a climate activist and I have be professionally focused on this planetary health crisis so that I can do whatever is possible, whatever is within my power to help support young kids like my own to have healthier world in the future.

Tell me, tell me about your son.

Oh, yeah, sure. He's 10 months old now. His name is Atlas.

Atlas.

Yeah.

Is Atlas going to carry the world on his shoulders?

You know, obviously, this is the remark that I, poor kid, I've given him to have to live down in every conversation for the rest of his life. We were thinking of it as strength, strength to be able to deal with a heavy world and to weather the storms rather than the burden that comes with it. But I guess it's an interesting reflection, of course, on the whole issue of climate change.

What do you think Atlas? What do think his life will be like? I don't know, 70, 80 years from now.

Mm, really hard one to answer. I see a lot of destruction and a lot of difficulty and parts of the world perhaps being quite uninhabitable. And that will bring about social strife in proportions that I do not wish upon any of these innocent people who be having to deal with it. But I also see there being wonderful pockets of figuring things out and regenerating landscapes and ecosystems. Of course, I have no idea what I'm talking about. I don't know what it's going to look like. And I feel much more comfortable staying in that gray zone and saying, I really don't now. I really didn't know and I don' need to know, you know? What I can do is use that uncertainty to fill my imagination about what could be possible in radically hopeful ways and then just fight for it. No matter what comes. And if it gets harder and harder and worse and worse, the way that we bring about the hope is by using it as a verb. It's something active and doing it together with others no matter how dark it gets.

That was Britt Wray, author of Generation Dread: Finding Purpose in an Age of Climate Crisis. And my first conversation was with Dr. Melissa Lem, a family physician and president of the Canadian Association of Physicians for the Environment. Thank you so much for listening and happy Earth Day. Chasing Life is a production of CNN Audio. Our podcast is produced by Eryn Matthewson, Jennifer Lai, Grace Walker, Lori Galloretta, Jesse Remedios, Sofia Sanchez, and Kyra Dahring. Andrea Kane is our medical writer. Our senior producer is Dan Bloom. Amanda Sealy is our showrunner. Dan Dzula is our technical director, and the executive producer of CNN audio is Steve Lickteig. With support from Jamus Andrest, John Dianora, Haley Thomas. Alex Manasseri, Robert Mathers, Leni Steinhardt, Nicole Pesaru, and Lisa Namarow. Special thanks to Ben Tinker and Nadia Kunang of CNN Health and Wendy Brundage.