That Neuroscience Guy - Your Brain on Nature

Episode Date: October 31, 2021

Going out for a hike or walking through the park can instantly improve your mood. But why does simply being outside make us feel better? In today's episode of That Neuroscience Guy, we get outdoors and discuss why being in nature is beneficial for your brain. 

Hi, my name is Olof Kregolsen, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. Have you ever thought about what's going on in your brain when you're outside in nature? You might hear some noise in the background because today's podcast I'm recording in nature. I'm walking along the beach in Tofino, BC and it's a beautiful morning. And I feel great. So what is it about nature that makes us feel so good?

What's going on in our brains? On today's podcast, I'm going to talk about the neuroscience of being in nature. To begin with, when we're outside in the world experiencing nature, our sensory system is ramped up. There are a whole bunch of research studies that show that when we're out in nature, the sensory input that we receive, for instance in our visual system, is enhanced. It's one way we talk about this in neuroscience is gain. So the gain of an amplifier is how much it amplifies the sound. The gain of the visual system

is how much it amplifies incoming visual input. So for instance, right now as I look out at the ocean, it's a vivid image. And it's a vivid image because my visual system is ramping it up. Now there is some room for individual differences here. Some of us don't like nature as much as others and for those people the brain wouldn't be ramping up the gain as much as it does for the rest of us. However the vast majority of people experience this phenomenon. Recorded EEG signals and even showing scenes of nature in an fMRI scanner, highlight that our brain is almost like on steroids when we're in nature.

And this is true for the other sensory systems. If you've ever listened to the sound of the crashing waves, the sound you might hear faintly in the background, well, it's the same thing. The gain of the auditory system, so the primary auditory cortex, which we talked about in a previous episode, is dialed up. And that sound is enhancing things in terms of sensory processing. But what else is going on in our brains? Well, one of the things that happens is our emotional system also gets ramped up.

For most of us, our amygdala is more active when we're outside in nature. So, for instance, you feel like you really love this and it's really pleasant. Well, it's because the amygdala is firing and basically agreeing with you. In fact, it's the other way around. The amygdala is actually driving that feeling inside of you. And in fact, it's the other way around. The amygdala is actually driving that feeling inside of you. So your emotional system, when you're outside in nature, is also hyperactive. Now, if you combine those things with the enhanced activity of the emotional system, what you get is the experience. When you're standing on a beach like I am, staring out at the waves and the sun's coming up,

and you just go, wow, what a beautiful scene. Well, that's because your brain is literally getting enhanced visual information, enhanced auditory information. It is true for the other senses as well. And then you combine that with this enhanced emotional response, and that's the experience of nature. Now when we're outside in nature there is other responses that occur. For instance a lot of people find nature to be calming. So if you're out for a walk in a forest for instance it's a calming relaxing feeling. And why is that? Well, again, this is the response of your brain. So, for instance, one of the neurotransmitters that plays a key role in this is cortisol.

Increased levels of cortisol have been associated with stress. Basically, the more cortisol that's released in the brain, the more stressed you are, the more anxious you are, the more nervous you are. And research has again shown that when we're outside in nature, we produce less cortisol. Our stress responses are reduced. In other words, we feel better. The same is true of increased releases of neurotransmitter. When we're outside in nature, again, research shows that the levels of dopamine in the brain, and if you think back to previous episodes, dopamine has been associated with feelings of pleasure and feeling good.

And of course, when we talk about learning, reward. So your brain, when you're outside experiencing nature, is releasing less cortisol. Your brain, when you're outside experiencing nature, is releasing less cortisol, so you're less stressed and less anxious, and it's releasing more dopamine, so you're getting this rewarding feeling of happiness. Now if you put all this together, it gets kind of cool. You've got enhanced sensory input, you've got increased activity in your emotional system, you've got reduced levels of cortisol, and you've also got increased levels of dopamine. Together, this adds up to a positive experience for your brain.

That's why tons of studies have shown that if you're stressed or you're anxious or you're depressed, simply going for a walk outside might help with your stress levels. Make you feel better. That's because that's your brain's reaction to what's happening. Your sensory system is enhanced. Your emotional system is enhanced. And as I said previously, those levels of cortisol are reduced. And those levels of dopamine are increased.

So in other words, what I'm trying to do is sell you on nature. And it's important because your brain's behind that cell. Your brain loves being outside. Being in nature has some other interesting benefits as well. There was a study done by a former colleague of mine at Dalhousie University. There was a study done by a former colleague of mine at Dalhousie University, and what she did is she basically let students go for a walk outside in nature before they wrote a test. And that was compared to walking around in a city. And what she found is that when people wrote a test following the walk in nature, they outperformed the people that had just gone for a walk around a city block. Now why is that? Well this is again tied to your brain's response.

Your brain likes being in nature and the impact of that isn't just instantaneous. So those enhanced neural functions that we saw, in particular the reduction in cortisol and the increase in dopaminergic release, those carry over for some period of time following being outside in nature. And that's why students performed higher on the test following a walk in nature than when they just walked around a city block. So in other words, one of the take-home pieces of advice you could get from this is if you have an important business meeting or you need to make some crucial decisions, you're probably far better off to go for a walk outside in a park

than you are just to walk around the city blocks where you live. Research from my own laboratory supports this as well. We did a study a couple years ago where we had students walk for 15 minutes outside and the control was walking for 15 minutes inside. And what we did is we used EEG technology to measure their brain function before they walked and after they walked. And what we found was really interesting. In line with a whole bunch of research that highlights the benefits of exercise on brain function, we found that after a walk, brain function was enhanced. So even after a 15-minute walk, we saw larger brain responses,

which are associated with better brain function. Interestingly though, that degree of enhancement was greater for the group that walked outside. So in other words, exercise does enhance brain function, but if you combine it with being in nature, you get an even greater enhancement. So there's another take-home piece of advice. If you're going to go for a walk, try to do it outside. Now in the case of our study, they were walking through nature. We were lucky enough at the University of Victoria that there's lots of forested areas on campus that you can go for a walk in. But when we ran the follow-up study, we found that just being outside was beneficial.

In the follow-up study, we looked at people walking inside versus people walking outside. But when they were walking outside, they were just walking around the city area. And again, the effect held true. Simply being outside, even if it's in a city, is good for you. Now, it's not as good as getting out into a park or the actual wilderness, but just being outside has benefits. And it's all tied to this idea of nature and the enhancement of brain function we see

that is simply triggered by being outside. There is even more cool research about the benefits of the brain being exposed to nature. Another area of the brain that's impacted by nature is the prefrontal cortex. Now, if you recall, the prefrontal cortex is associated with decision-making and executive function. It's the high-level stuff that basically makes us human, our ability to goal plan and make decisions. One of my favorite studies that supports the benefits of the brain being exposed to nature highlights this. Specifically, researchers from the University of Utah used portable EEG systems to track activity of the brain, and specifically

the prefrontal cortex, when people were outside in nature. And what they found was that activity in the prefrontal cortex was reduced when people were outside in nature, relative to when they were just in a regular city environment. Now, what does that actually mean? Well, the interpretation made by the researchers, which is supported by additional studies, is that your brain's almost like on a bit of a holiday. It's going, okay, I don't need to be as active right now. I'm in this environment that doesn't require a lot of prefrontal cortex activity. Now, obviously, if you started doing things in nature like rock climbing or surfing, that would change radically. But the

research was pretty clear that if you're just in a nice relaxing nature environment, there's less activity in the prefrontal cortex than when you're in a city environment. And that's good because your prefrontal cortex needs time off. It needs a vacation. Now my favorite part about this particular study is then they looked at what happened next. So what happened to people that were exposed to nature when they went inside again and had to take on their daily tasks? What they found was that the prefrontal cortex had ramped up and people that had been outside in nature had this rebound where their brains were more efficient in performing at a higher level following time in nature. So it's kind of cool when you put it together.

When you go outside in nature, the prefrontal cortex is taking a vacation. It's less active and resting, if you will. But when you come back from nature to daily life, the prefrontal cortex is functioning more efficiently. So it's kind of cool, this dissociation, where your prefrontal cortex activity is down when you're in nature, taking a rest, and then rebounds to perform at a higher level when you come back from your time outside. So, what's the take home message about the neuroscience of nature? Well, quite simply, you get enhanced sensory processing,

you get enhanced emotional responses, you get reduction in cortisol levels, which are associated with less stress and less anxiety, and you get enhanced release of dopamine, which is associated with pleasure and reward so i guess what i'm telling you is you should spend more time in nature because your brain will really appreciate it and it will respond accordingly all right that's all i have for this episode i'll see you next week on the podcast don't forget you can follow me on twitter at that neuroscience guy

you can also check out our youtube channel that ThatNeuroscienceGuy. There's not a lot of content there yet, but we're trying to grow it every week. You can also email us if you have ideas for the podcast. We've got a few coming in that we're going to incorporate into future episodes, but please reach out, ThatNeuroscienceGuy at gmail.com. My name is Olaf Kregolsen, and I'm That Neuroscience Guy. Thanks for listening, and see you next week.