Neurosustainability & the Built Environment-Why Your Brain Needs Better Cities

[00:00:00]Voice Over: This is Constructive Voices. Constructive Voices, the podcast for the construction people with news, views and expert interviews. [00:00:12] Mark: Welcome to the Constructive Voices miniseries that dives into neurosustainability and the built environment. We investigate the work of Cambridge scholarship student Mohammad Hesham Khalil, which we believe should be integrated into planning and architecture around the world. Mohammed also brings other top global experts to your ears during this short series of podcasts. By the way, this episode is very rich in information that we believe many of you will wish to dig into further. For this reason, the episode's written information page contains a section for further exploration with a variety of scientific references. [00:00:52] Jackie De Burca: Good morning or good afternoon. This is Jackie De Burca here from Constructive Voices. I have what I believe will be a very fascinating interview for you today. I'm with Mohammad Hesham Coming Khalil. And he is currently working on an amazing theory of neurosustainability which is linked to the built environment. For the benefits of our listeners at Constructive Voices. Mohamed, thanks for taking the time to be here with us today. Can you just introduce yourself briefly? [00:01:19] Mohamed Hesham Khalil: My pleasure. Hello, everyone. I am Mohammed. I'm an architect, researcher in neuroscience, and a PhD candidate at the University of Cambridge, exploring the intersection of environmental enrichment and neurogenesis as part of a work towards achieving your sustainability. Specifically, my focus on environment enrichment begins with the urban environment and then extends to architectural applications to enhance neurogenesis through motor, cognitive and visual enrichment. [00:01:47] Jackie De Burca: What first drew you to explore this intersection between neuroscience and architecture? [00:01:54] Mohamed Hesham Khalil: It was during lockdown, to be honest, when I started seeing so many people feeling more depressed and having higher levels of anxiety, that was sparked to something that it is something about the built environment, and especially that some people have sustained those symptoms even after lockdown. So that shift from experiencing the built environment in a specific way and then going back was an alert to. To start seeing this relationship between the built environment and the human brain, because I know that it is associated with mental health and cognitive performance was really the motivation. And I started like exploring this during my Master's. It was interdisciplinary between architecture and neuroscience, applied neuroscience specifically. And then that was the departure point, based on which I started doing my PhD at the University of Cambridge to explore this impact of the built environment on neuroplasticity in more depth. [00:03:01] Jackie De Burca: Okay, fantastic. Now tell me in a little bit more depth, Mohammed, what was it about lockdown and the brain that you observed? [00:03:09] Mohamed Hesham Khalil: Well, basically that was confirmed later on during a pilot study we have done here at Cambridge, but it was about the reduced extent of exposure to something we call in Science, spatial complexity, it's abundant in the outdoor environment and it's more abundant in natural environments than in urban environments. But when we spend more time indoors, that is really not good for our brains. And there is a growing evidence. It's scarce, but there is enough evidence to support this hypothesis is not just due to the loss of exposure to high spatial complexity, but also reduced frequencies of physical activity, depression and anxiety, even in among healthy subjects, not with major depressive disorder. But we already know that there are some studies that have shown that people who were physically active at home have reduced levels of depression and anxiety. And science says that depression and part of the brain, specifically the dentate gyrus in the hippocampus, where something called neurogenesis takes place. And some biomarkers are, you know, they form like a triangle that tells a lot about how the built environment affects this internal biological environment. Going back out to the outdoors where people can have more active lifestyles, greater exposure to spatial complexity and so on, was the antidote. [00:04:36] Jackie De Burca: I mean, it's just such a fascinating topic because I think, you know, with COVID and lockdown only a few years ago, we're recording this in 2025. You know, it's still something that has affected people and members of their families in various ways. And so this topic, even though it's very scientific, I think it's very relatable still to people, isn't it? [00:04:54] Mohamed Hesham Khalil: I agree. [00:04:55] Jackie De Burca: So you yourself, obviously you've been in a few different environments for your work and your studies, Cairo, Boston and Cambridge. Have you noticed how those environments have actually influenced your own thinking about space and well being? [00:05:08] Mohamed Hesham Khalil: Yeah, actually, because part of spatial complexity, you know, just like to explain it briefly before I explain how I related specifically to this experience. We don't have available evidence on humans about spatial complexity, but we have a lot of evidence based on animal models. And this may be like ironic, but the human brain and animal brains are to a great extent are similar. So changing the environment, this process itself is a renewal of the spatial complexity to which we are exposed. Moving from one country to another and then going back. After some time working on my PhD and going back, I started noticing those shifts. And that was supporting the hypothesis that I had in mind that not just the loss of physical activity that was affecting the overall mood, but because physical activity is part like it is free living, you don't have to make it systematic. But also changing place is reported in a couple of studies to be improving mood and also improving cognitive performance. So it's really healthy. It is getting exposed to different types of spatial complexity in different contexts and regions. [00:06:18] Jackie De Burca: I can agree with you because as some people already know, I am Irish and I've lived in Spain for an awfully long time, but I've also lived in Greece and also in the uk, so I have a little bit of my own experience of that. And I could say also that, yeah, when I come back over to Spain, having visited Ireland, I find this whole process that you've just explained very well. [00:06:38] Mohamed Hesham Khalil: Yeah, I know. And you have, like, fascinating stories about how that sparked creativity as well. [00:06:42] Jackie De Burca: Absolutely. So let's go in to the actual main focus of your work, the main keyword, if you like newer sustainability. How would you explain it, Mohammed, to somebody who's hearing that for the first time? [00:06:55] Mohamed Hesham Khalil: Yeah. So, first of all, the brain is not concrete. So it is always changing. And some changes can be observed at short term, others as long term, but it is changing. So the brain is changing in a positive way when it is in natural environment. So when we use the word sustainability for preserving the planet, it has to be inclusive and include the brain as well. So that was my intention to highlight neurosustainability as a way of living, building and sustaining the health at different levels. We can say cognitive, mental and more, but it is an inclusive word that also challenges existing paradigms. And also because the word new architecture that is overly used is taking different direction and is focusing mainly about the cognitive processes and more, it's more behavioral. So I thought that we need a fresh keyword, highlights something that has been overlooked or not. Given that great attention. Despite that, it is very critical, as we saw during lockdown. [00:08:03] Jackie De Burca: Absolutely. So, yeah, of course there was a lot of jokes on social media. People will remember this, people getting dogs, you know, for the sake of being able to get out into nature and all that type of stuff. Now you focus obviously on spatial complexity that you've already touched on and environmental enrichment. How do these impact the brain on a biological level? [00:08:20] Mohamed Hesham Khalil: Yeah. So we learn a lot about environment enrichment from rodent models because they're in a controlled environment from birth to death. And researchers have been able to understand the impact of spatial complexity, running wheels and so on. So we came to understand that an enriched environment, regardless of how we define it for an animal model or a human subject, is something that is vital to nurture the human brain. And that is what the human brain needs to nurture and support its neuroplastic responses. It can change in a good way, which can be reflected in an increased brain volume, increased biomarker levels, such as we call them the growth factors. There is one called brain derived neurotrophic factor, BDNF among others. The link between environmental enrichment and that outcome that we say that cognitive performance and mental health has too additional steps in the middle. So first exposure to environment enrichment starts to increase the levels of those growth factors that are associated with a lot of other molecular mechanisms. But that in turn is taken to improve the cognitive performance. It acts as an antidepressant as well, as shown in a lot of research. And at the same time it contributes towards enhancing the neuroplasticity of the brain by increasing its volume in response to synaptic plasticity or neurogenesis. But neurogenesis is really something that's very niche. It is, you know, it's about memory, but overall it's a really linear and prolonged process that makes us reconsider if we are taking environmental enrichment in our own environments for granted and if we really need a new model for us as humans who are building their own environment. [00:10:09] Jackie De Burca: What role Mohammed does everyday built environment play in shaping mental health, especially in cities? [00:10:15] Mohamed Hesham Khalil: Yeah. With the rapid increase of urbanization, there are lots of things to talk about. First of all, spatial complexity, of course, and how the environment promotes and encourages everyday physical activity. That can be a moderate intensity walk or cycling. The more we rely on transportation, the more we are exposed to build further than natural environments. We're losing more of the essence found in nature. And that in turn, you know, it doesn't provide the brain with what it needs. [00:10:43] Jackie De Burca: Okay, so I suppose one of the things I was thinking about as I was researching, you know, your work prior to our chat today is our use of cars, transport, different types of transport, and our being indoors is really only a couple of centuries old, isn't it? So if you compare that with such a long period before and then I know it's a different topic. But if you look at genetic hand downs from our ancestors, genetic memory, all that type of stuff, it's not natural for us to be stuck in boxes and in transport systems that are mechanical, is it? [00:11:15] Mohamed Hesham Khalil: Yeah, exactly. And it's very critical for our evolution. Why we need to reconsider, consider this is because we are moving forward. And if we look forward, it would be like maybe not good for our brains. Maybe the next generation will not benefit from what we're doing right now. So yeah, we may really touch on important topics that may seem irrelevant, but they are part of this debate. Climate change, for instance, it is affecting the innate spatial complexity found in nature. So we are not just building environments that are in which. But we need to sustain the environment enrichment that is found in nature. And also, like you mentioned, transportation is really important because pollution has been found to impair the increase in growth factors and other molecules. Even if we make our environments more green, if there is high air pollution that has it, it's called like an antagonistic variable, so counteracts the positive impact of. Of an enriched element. So it's really complicated and complex, but it's really important to look at every single. What is environment enrichment? It's not just about physical activity and spatial complexity. It's embedded in the problems we have in our generation. [00:12:24] Jackie De Burca: Just because it's one of the topics that has been discussed in previous episodes, the law of biodiversity and that gain that came into effect in the uk. And yet at the same time, there's been so many new discussions and tweaking and uncertainty about it. One of the selling points that we tried to propose with some of our guests was if you're developing an urbanization, why not incorporate a lot of nature and don't destroy the existing nature? Because at the end of the day, it will then be more desirable to people who want to actually invest or live there. [00:12:53] Mohamed Hesham Khalil: Exactly. I can understand why this was not given enough attention or care, because it was just very recently when more evidence came out to show that, yeah, a green environment has an impact on the brain and a built environment also has an impact, but it's a different one. So having the responsibility towards sustainability, I can see coming as not just towards saving the planet anymore, but we are doing it for ourselves, before the planet and through the planet as well. So I can see a paradigm shift coming soon. [00:13:23] Jackie De Burca: Yeah, and that's obviously going to be very welcome. Unfortunately, again, not being cynical, but being just very honest about people that we've spoken to and research that we've done. Unfortunately, as human beings, the ego stands in the way of various potential progress. And when you speak to people about what's going to benefit them and their families and their wallet, they can relate to that. Before, unfortunately, unfortunately, the bigger issues. [00:13:44] Mohamed Hesham Khalil: Yeah, absolutely. There is upcoming research on this. I cannot tell more about it at the moment, unfortunately. But yeah, you're absolutely right. It is something that, you know, people think of things that mean to them before, you know, thinking about what is more important, like for the planet or whatever that is like for the greater good. But that's it. It's really. It's not separate, it's two sides of the same thing. [00:14:09] Jackie De Burca: Mm. It is Absolutely. Two sides of the same coin in your studies. Mohammed, on walking, which fascinates me, hippocampal function, what were some of the most surprising or affirming results that you got? [00:14:22] Mohamed Hesham Khalil: Yeah, it was really impressive because it is not just that the hippocampus increases in response to, you know, more step count and higher walking intensities, but it's also the walkability in the built environment. Every extra 1km of walkability can be less. There is a linear association between the increase in the hippocampal volume and the increase in the walkability in cities. So it is not just visual and it's not just about pollution, but it's also about the two dimensional element of cities. The other one was that the hippocampus itself is very complex and each part of it responds differently to walking. So the part about emotional regulation benefits more from a lower intensity walk in a natural environment that is restorative. While a high intensity walk, for instance, increases the volume of other parts in the hippocampus that are responsible for cognitive function. So it's really fascinating that there is no single solution, but we need this diversity and we need this complexity. [00:15:25] Jackie De Burca: Now I'm going to ask you the favor of a brief explanation where the hippocampus is and what it does in simplistic terms. [00:15:32] Mohamed Hesham Khalil: Yeah. So we have, at the outer part of the brain, we have the frontal cortex, the parietal cortex and so, and the, the occipital one, the temporal lobe as well. So that's the main part that many people see when they get to see a real image of a brain. But deep inside, in the middle part of the limbic system, we have one hippocampus at the right and left hemispheres. It is given that name because it really looks like a hippocampus. So it is, as any other part of the human brain changes in volume as well in response to the environment and lifestyle. [00:16:07] Jackie De Burca: How do you go about measuring things like the environmental affordance or spatial complexity? [00:16:13] Mohamed Hesham Khalil: Yeah, so currently I've been working on spatial complexity for over a year because that is translatable from rodent models. But the one I've published already about environmental affordance for physical activity is about how well the environment can provide walkable spaces and stairs, cycling opportunities, which in turn, as we said earlier, increases the growth factors in the human brain and the peripheral nervous system as well that are important for nurturing the neuroplasticity. Because, you know, we. In this model, I quantified the environmental affordance for physical activity through the energy Cost, specifically using metabolic equivalents. For instance, if you walk with a moderate intensity of 100 steps per minute, that is equivalent to a moderate intensity physical activity that is greater than 3 metabolic equivalents in your resting state, you have a metabolic equivalence of just 1 from 3.5 metabolic equivalents and going higher. This increases the chance of increasing the levels of the growth factors in the brain that we mentioned earlier, which in turn start to regulate neurogenesis in the hippocampus, which means the birth of new neurons in the brain. It has been shown recently that this process persists even into the tenth decade of human life. So we should not take this for granted. It's really vital. And also the increase of those growth factors is important for increasing brain volume. It is involved in synaptic plasticity and so on. So it starts with the step count, but every step count really counts towards improved brain response. [00:17:50] Jackie De Burca: It's amazing. It's amazing when you think about it. I'm never going to walk in the same way again. [00:17:53] Mohamed Hesham Khalil: Yeah, that is good. In a different way. [00:17:57] Jackie De Burca: Yeah, that is just when you plant like that seed of what's going on, you know, really is absolutely fascinating. Can you just walk us through like any of your research points from design to what you discovered? [00:18:08] Mohamed Hesham Khalil: I've been working on designing some experiments, if that's what you are asking about. We are always faced by methodological limitations in the domain of architecture because it is still growing and it's. It's really difficult to get ethical approvals for taking blood samples from people, for instance, when you're doing this important research. It's interdisciplinary, but it needs bigger teams and so on. So we have a lot of experiment designs we're working on, but still the execution is taking time due to those limitations. [00:18:38] Jackie De Burca: Hmm, okay, that's understandable I suppose. Again this is just brainstorming as we chat. The ideal situation would be to have some partnerships in place with some of the pro sustainable builders, for example. [00:18:50] Mohamed Hesham Khalil: Yeah, exactly. And I think that in the industry as well, well start seeing the importance of this. I know that some are already having their own departments and they have a priority of how their own designed environments are impacting the brain. So yeah, it is growing and people are taking seriously in industries. I can see that the translatability of science into the industry as well happening very soon. Even if we have the current evidence, not just purely theoretical, but theoretically supported by evidence from other animal models and other synthesized human based evidence, not just from walking, but maybe gardening. Gardening is proven to increase that growth factor in the brain. So if we prove that walking at that intensity or using steer that way is sufficient, then it is to a great extent proven and it is translatable into the practice right away. [00:19:48] Jackie De Burca: Absolutely. So in your opinion, with the research you've done, how can the likes of architects and planners and developers begin to apply neurosustainability principles today? [00:19:58] Mohamed Hesham Khalil: Yeah, there are lots of ways that can be done. I think the first and foremost is to increase walkability and free living physical activity opportunities. That is through encouraging stereos, for example, because. Because I've seen that stairs have been like kept for emergency situations only and it is no longer an option to skip the stairs and take the elevator. It has been the norm. So yeah, I think architects can start looking at the building layout in a different way because the use of the layout itself affects the brain in different ways. One through physical activity, another through the opportunities of change it proposes. If you have just one, one single way of experiencing a layout that is monotonous and that is not helping. So that is at the layout side of the architecture. But also architecture is multidimensional and we have it's visual and it is part of the indoor and outdoor environment. So it's liminal as well. So yeah, we can bring spatial complexity to the conversation. When it comes to architectural design, having architectural facades with the high spatial complexity, you know, it forms the overall spatial complexity of the city. So I think they should start paying attention to the impact of the architecture because architecture at the end becomes the architect and our brains in response to it. So that's for architects and for urban planners and designers. I think they should start promoting, as we said, similarly to architects, layouts that are not monotonous, they're more diverse. Research shows that layout complexity in urban environments is promoting increased hippocampal volumes and reduced cases of Alzheimer's disease and mild cognitive impairment as well. And also two more important topics are air pollution on tree cover, density that, you know, they interact with each other. But having an environment that is low in pollution and rich in greenness at the same time is vital. It's vital for neuroplasticity. [00:22:07] Jackie De Burca: I mean, it's all so interesting. And again, like yourself, somebody who's changed environments, I can identify with that maybe quicker than some other people who have stayed most of their life in the same environment. Mohammed, are there any examples of buildings or urban areas that already reflect these ideas, even if somewhat unintentionally? [00:22:26] Mohamed Hesham Khalil: To be honest, I've been purposely not building my science and theory on specific case studies because I want to start the other way and then see if different buildings or urban environments fulfill what spatial complexity defines itself or environmental affordance for physical activity, for instance. But there are some comparisons between different states, for instance, in the usa, that some urban grid patterns are more uniform than others. Based on the evidence that we have right now about the layout complexity in urban environments, I think it should shift the attention a little bit and urge those different cities and states to revisit how to compensate for the loss of spatial complexity in their own layout. [00:23:11] Jackie De Burca: Okay, so what policy changes or planning guidelines would you love to see adopted that would support brain friendly environments? [00:23:20] Mohamed Hesham Khalil: That's really interesting because I know that a lot of policies are already including sections about health and well being, but that is purely based on evidence that is based on self reported outcomes and things that are not objectively measured. So I think changing that a little bit to start defining what's needed based on the hard science is really what's needed specifically in the practice of sustainability. Because that can be. I think it's already embedded in sustainability, but it's not framed well. I think revisiting the terminology is used to give more attention to certain points and sections that may be overlooked because more attention is given to economic sustainability or social sustainability. They're giving greater priority. [00:24:09] Jackie De Burca: Sure. I mean, just throwing out a term that some people will be familiar with because we're going to look at the built environment in more depth now that we've introduced the actual concept. Biophilic design is obviously something that is kind of linked to your research in its own way, even though it's not. It's a separate body, if you like. [00:24:25] Mohamed Hesham Khalil: Yeah, it's not separate at all. And there is a piece I'm working on right now about biophilic design because it stands out a little bit as different, even different from green architecture. But biophilic architecture specifically is more inclusive and our brains are biophilic. So translating the current evidence we have about green environments is really important and vital so that we understand how biophilic architecture and biophilic interiors can in turn be promoters of newer sustainability. Because yeah, we are exposed to indoor environments more than outdoor environments. And this is an alert that we need to really pay attention to how we design indoor environments through the architecture and through the interior setting as well. So I see biophilia as trend, brain health and neurosustainability as well. [00:25:18] Jackie De Burca: Okay, that's perfect. That's the perfect answer really because we're going to dig a lot deeper in the second episode of this mini series into the built environment, what's wrong with it, what can be done and so on, so forth. You've touched on that very nicely. If listeners, Mohammed, could just take away one idea from this conversation, what would you hope that would be? [00:25:35] Mohamed Hesham Khalil: That would be to go back to nature. That's the way to be more sustainable. And we are doing this by translating nature has into our own built environments. So that's for architects and urban planners and for everybody. I would suggest walking, walk as much as you can. Change your routine. All of those things are lifestyle based promoters of your sustainability. [00:25:58] Jackie De Burca: They absolutely are. And I just brought to mind a quote from another guest quite recently and it was something along the lines of, you know, what you do for nature, Nature, nature multiplies it tenfold. Something along those lines. [00:26:10] Mohamed Hesham Khalil: Ah, that's really in line with what we are talking about. [00:26:14] Jackie De Burca: Listen, it's been an absolute pleasure. I'm looking forward to our future conversations. Mohammed, this is a pure introduction and we're going to delve a lot deeper and try to find solutions and takeaways for people who are in the built environment, who are our main audience, but even for those who aren't. [00:26:27] Mohamed Hesham Khalil: Thank you Jackie. [00:26:28] Jackie De Burca: Thank you so much. [00:26:29] Mark: We hope you enjoyed listening to this as much as we enjoyed making it. If you have projects or information that relates to this topic or the area of sustainability in the built environment in general, you may be eligible to be featured on the new Constructive Voices Global Directory. Be sure to email findonstructive-voices.com with a few lines about your company to discover more about this. [00:26:54] Voice over: This is Constructive Voices.