Cleo Valentine: We now know architecture can cause stress

Cleo Valentine. Image: Archive of Cleo Valentine

Cleo Valentine is a doctoral candidate at the University of Cambridge. Her research focuses on examining the impact of architectural form on neuroimmunology and neuroinflammation. Cleo received her MPhil in Architecture and Urban Studies from the University of Cambridge, MSc in Sustainable Urban Development at the University of Oxford and Bachelor’s in Urban Systems and Economics from McGill University and the University of Copenhagen.

She has worked as a computational systems designer at Open Systems Lab (formerly Wikihouse), has held positions as the Neuroaesthetics Fellow at The Centre for Conscious Design and as a guest tutor at the Royal College of Art and the Architecture Association in London. She is currently an associate at Cambridge Architectural Research Ltd., where she provides consultancy services on public health and architecture.

Natalia Olszewska: I’m excited to talk to you because this is going to be a conversation where we can dive deep into human physiology and how it relates to architecture. What brought you to neuroarchitecture in the first place?

Cleo Valentine: My interest in neuroarchitecture comes from both my academic and personal experience. I first studied at McGill University in Montreal, where I did a program called Urban Systems.

It was at the intersection of urban studies and human geography, examining how people move through space and how urban environments evolve over time. It gave me an interdisciplinary approach to studying architecture and cities.

The Human Scale documentary about the work of urbanist Jan Gehl. Image:

While at McGill, I had the opportunity to study at the University of Copenhagen on an exchange program. I became interested in going there after watching ‘The Human Scale’.

The documentary focuses on the visionary work of Danish architect and urban planner Jan Gehl of Gehl People. To me, his work underscored how the rapid expansion of cities presents an opportunity to reimagine urban planning to prioritize people’s well-being and health.

I thought it was an important emerging field, so I ended up going to Oxford University to do my Masters in Sustainable Urban Development. There I immersed myself in the literature on neuroaesthetics, evolutionary biology, and neuroimmunology.

I wanted to know if there was a connection between certain design choices, people’s perceptions of beauty, and human health. This eventually evolved into a fascination with how architecture might affect our brain through our immune system.

My research at Oxford used machine learning image analysis to investigate the impact of biomorphic architectural geometries on public health using census data.

I wanted to see if people were healthier in places where they perceived the architecture to be more beautiful. The results of this experiment were encouraging and suggested that incorporating certain biomorphic principles into architectural design could have benefits for people.

Biomorphic forms and patterns can be found in architecture around the world. Image: Nicole Fahey

Then COVID happened, and for a number of reasons I became interested in the role of the immune system in our health, especially our neurological health. Until recently, it was thought that the brain was “immune privileged” – meaning that the immune system had no effect on it. However, we now know that this is not the case. In fact, the two are intimately connected.

The immune system is greatly affected by stress, and stress can take many forms. For example, stress-inducing triggers can be microbial, such as bacteria or viruses, or environmental, such as air or light pollution.

I wondered, “Could architecture have similar effects?” It turns out that it very well might! We know that some architectural forms have been associated with stress. I am now interested in whether exposure to these architectural stressors affects our neuroimmunology.

What is architectural stress?

Natalia: Fascinating and so interdisciplinary because you talked about working at the intersection of so many different fields. And answers to complex questions can only be found at this intersection. I am impressed by the breadth of your horizons and your curiosity.

We know that there are some principles behind human physiology, such as homeostasis or allostasis, and I think they are relevant to your research. Could you explain to our readers what they are, what the stress response is, and how it relates to inflammation in our brains?

Cleo: It’s helpful to start with homeostasis, which is a self-regulating process that allows all living organisms to maintain internal stability and balance while adapting to changing external conditions.

We are constantly exposed to threats, some real and some perceived. To the body, however, the difference doesn’t really matter. This is where architecture is particularly interesting, because potential spatial threats can be found in everything – noise, inadequate lighting, or when it’s difficult to navigate space.

Spaces like hospital corridors can make orientation difficult and create stressful conditions. Image: Kenny Eliason

I always use the example of trying to find the exit at Ikea. It’s very stressful. Or trying to navigate through a hospital – spaces where the signage isn’t very clear and you can’t spatially locate yourself in relation to the outside. Our minds can subconsciously perceive these environments as threatening, even though there’s no inherent danger.

When you’re exposed to a threat, there’s a series of physiological changes in the body that allow you to avoid that threat. Suddenly you’re pushed out of homeostasis, your stable, normal state, and into a state called allostasis. So, when we encounter an architectural stressor, our bodies are pushed out of homeostasis and into allostasis for – potentially – no real reason.

Natalia: It’s an adaptive response.

Cleo: Yes. Your allostatic response can cause your heart rate to increase to pump more blood to your muscles, heart, and vital organs. It can cause increased blood pressure and breathing to get more oxygen to your lungs and brain, and release blood sugar and fat stores for additional energy.

The stress response has a bad connotation, but in the short term it’s actually an important physiological process and not necessarily bad in itself. It is what allows us to survive, thrive, and escape from all kinds of threatening situations.

Allostatic stress response. Image: Cleo Valentine

Natalia: Hans Selye was an endocrinologist who is credited with inventing the word “stress”. He was one of the scientists who laid the foundation for the field of psychoneuroimmunology, which studies the interplay between the mind, nervous system, and immune system.

As a medical student, I was very interested in his work. He used to distinguish between eustress (positive stress), which helps us stay motivated and up to challenges, and distress (negative stress), which is severe and prolonged stress.

Cleo: Yes, absolutely! When we think about architectural design, the threat is perceived rather than real, so perhaps we could always categorize stress related to architectural design as distress. The pressing issue for me is the level of exposure to architecture.

Where our built environment includes stress-inducing architectural forms, we are repeatedly exposed, repeatedly pushed out of homeostasis.

A recent study found that Oxford residents spend an average of 95.6% of their time indoors. For many of us, there is no escaping the built environment – it is an integral part of our modern lives.

This means that where our built environment includes stress-inducing architectural forms, we are repeatedly exposed, repeatedly pushed out of homeostasis.

When you are in a situation where you are repeatedly exposed to acute stressors, you are pushed into what is called allostatic overload. And when you go into allostatic overload, those stress responses that would be beneficial (or at least benign) can now become incredibly harmful.

What do architectural stress and inflammation have in common?

For example, if you go into allostatic overload, you can begin to experience conditions like chronic inflammation. Acute inflammation in response to a threat can be good, it is an adaptive response. It helps you fight off infection. Fever, for example, is part of that response. But when it happens repeatedly and often, it can become chronic.

Chronic inflammation can lead to a number of devastating psychiatric and neurodegenerative diseases such as anxiety, depression, schizophrenia, but also Alzheimer’s, Parkinson’s, or ALS.

We also see a significantly increased incidence of neuroinflammatory conditions in cities, and that’s even when we control for things like pollution, income deprivation, and other harmful social conditions.

How allostatic overload happens. Image: Cleo Valentine

We now know that architecture can cause stress, and that’s one of the things that the field of neuroarchitecture is looking at. And the field of neuroimmunology is looking at how stress responses can lead to neuroinflammation.

What hasn’t really been looked at is the connection between the three. That is what my research is looking at – what can our neurophysiology tell us about healthy buildings?

Natalia: Fascinating. Hans Selye, who I mentioned earlier, has studied the nature of the chronic stress response and the damage it does to rats. So what kind of body damage could result from prolonged environmental stress? Does it create some kind of imbalance from a hormonal point of view?

Cleo: Allostatic overload leads to a number of negative changes in the body. Personally, I am very interested in neuroinflammation, but chronic inflammation can also contribute to hypertension, heart disease, and diabetes. A state of chronic stress and inflammation can lead to hormonal changes and permanent tissue damage.

How could biomorphic and biophilic features contribute to health?

Michal Matlon: It’s a pretty exciting field to be a part of. Based on your research, what forms in architecture might be beneficial and what forms might provoke the stress response you were talking about?

Cleo: In my recent pilot study, I looked at visual exposure to biomorphic and biophilic architectural features in facades. I measured the level of biomorphism and biophilia using something called the Biophilic Healing Index, which was developed by Nikos Salingaros.

This framework allows you to assess the presence of certain architectural features. Although this was a pilot study which aimed to assess the feasibility of measuring neuroinflammatory responses to architectural design, the results were compelling.

Components of the biophilic index. Image:

The findings suggest that increased levels of biomorphic and biophilic design resulted in reduced neuroinflammatory activity. This could be good news for architects, because it means that certain design choices could have a positive impact on our health.

However, we definitely need a great deal more research before we can say with certainty – what precise design choices are good for human health.

Going forwards, I am looking to evaluate the geometric configuration of a space. I have isolated three key visual features of architecture which are of particular interest:

  1. Curvature, for example the incorporation of arches and vaulted ceilings
  2. Proportions, for example ceiling height and the ratio of a room’s depth to its width
  3. Room enclosure and the type of enclosure, such as window size

Of course, how we define these architectural forms varies considerably from study to study. So before we can even test the effect of these architectural forms on neuroimmunology, we need to think about how we define these qualities of the built environment.

Designers often have an understanding of these qualities, an informed intuition. But they often succumb to economic pressures. In such situations, the drive to cut costs can lead to decisions such as reducing window sizes, shrinking room dimensions, lowering ceiling heights, or simplifying the shape of the building.

An open room with high ceilings. Image: Toa Heftiba

I hope that as we gather more evidence, it will help to further justify prioritizing human health over short-term economic gain. Jan Gehl said, “… city planning has been going on for a number of years with a rather incomplete toolbox.” I hope that this research will eventually become one of those valuable tools.

Currently, every research project I’m involved in seems to generate more questions than it answers, and I see that as a positive development. If we can establish that specific architectural environments lead to changes in neuroinflammatory activity, it paves the way for further exploration by environmental psychologists, cognitive neuroscientists, and experts from various disciplines to delve into the underlying reasons for this phenomenon.

How can subtle, but long-term stress caused by architecture be harmful?

Natalia: At one point you talked about the degree or length of exposure to these stimuli in architecture. That can also be an important factor in how they affect us, right?

Cleo: There are still a lot of unanswered questions about how long you need to be exposed to harmful architecture to see negative effects. I think it is probably too early to say.

This is where the concept of allostatic load becomes interesting because it helps us understand the effects of chronic or long-term exposure to even low levels of stress.

I like to use the example of PTSD (Post Traumatic Stress Disorder) versus cPTSD (Complex Post Traumatic Stress Disorder) when talking about the effects of chronic traumatic stress. While PTSD can result from a single traumatic event, cPTSD results from ongoing trauma that persists over time.

Built environment consisting of sharp edges, angles, and straight lines can be more stress-inducing than that design with curves and smoothness. Image: Lance Anderson

Say you have a severe traumatic accident that immediately puts you into allostatic overload. It might be thirty seconds, very fast. But you can get to the same level of allostatic overload if you have a long series of really small stressors that keep pushing you out of homeostasis, into allostasis. But it happens slowly, over time.

Initially, many of our stress responses may seem benign. But when the neurophysiological effects are measured and observed, it becomes clear that over time these responses can contribute to adverse health outcomes.

In terms of architecture, it’s possible that the features that consistently produce minor stress responses in our bodies are the most insidious, precisely because they often go unnoticed.

How could architecture help fight the mental health crisis?

Michal: It seems that we need to start looking at our environment as part of the global response to the mental health crisis. We see increasing rates of different types of mental health issues, but very rarely is the impact of the built environment mentioned today.

Cleo: I don’t want to exaggerate the influence of architectural form or urban design on health. It’s certainly not true that changing one element of these environments will cure all these conditions and diseases.

But when you consider the many factors that affect health, such as diet, physical activity, smoking, medications, and exposure to pollution, it becomes clear that these components are pieces of a larger puzzle. Accepting the built environment as another important piece of this puzzle is critical.

Subscribe to Venetian Letter

You will receive our regular newsletter with blog posts, interviews, books and events on human-focused architecture and urban design.

Many people live their entire lives in the built environment, and they’re affected by it either positively or negatively at any given moment. No space is neutral.

It also raises an interesting bioethical question: do people consent to being in spaces that could harm them? Could we think about the effects of architecture in a similar way to how we think about secondhand smoke?

What happens if someone has to walk down a badly designed street to get to work, get on a train through a certain station, and they don’t have much choice about what that environment is going to be like?

In terms of architecture, it’s possible that the features that consistently produce minor stress responses in our bodies are the most insidious, precisely because they often go unnoticed.

Natalia: Do we know anything about the most vulnerable groups when it comes to the effects of environmental stress?

Cleo: Not definitively, not at this point. My understanding is that certain people may be more responsive to the environment than others.

First, we need to establish some baselines against which we can compare people. For example, we can look at our current understanding of blood sugar or blood pressure levels. The reason we know what a healthy range is, is because we have a tremendous amount of data from a number of different people all over the spectrum, a bell curve.

At this point, one of the challenges of architectural science is that so far, our sample size is small. We just haven’t had enough time to collect and analyze as much data as, say, medicine has. This makes it difficult to make clear, generalizable claims.

Could we think about the effects of architecture in a similar way to how we think about secondhand smoke?

Also, as in medicine, there are so many confounding factors that affect how people respond. One size does not fit all. But we are working to conduct rigorous science and gather as much information as we can.

The field is new, but so far, the results are both encouraging and alarming. I hope that this research can serve as a new tool for built environment professionals to positively impact public health. It is a great privilege to be able to contribute to this. But it also comes with a great deal of responsibility.

How could architects avoid creating stressful designs?

Michal: In another interview, you mentioned that if we had more knowledge, we could create a practical tool for architects to help them assess whether their designs are in line with what we consider to be beneficial, or at least not harmful. Could you tell us more about this?

Cleo: I think we can go three ways about implementing this research into practice:

1.   We can take a translational approach, where we apply the findings from clinical research in practice. This can be done through consulting or through experts working directly with architects, real estate developers, urban planners and designers.

2.    We could adopt an experimental approach, where we iteratively test the impact of a proposed design on our neurophysiology.

3.  Or, and this is something I am quite interested in, is the potential to combine the translational and experimental approach into something that is computationally based.

Biophilic building concept. Image: Studio Precht

This could take the form of a digital tool that dynamically analyzes the architect’s design as they draw it and provides real-time feedback based on current knowledge, providing the architect with a predicted probability of the physiological effects.

For example, say we have knowledge about the effects of different height-to-width ratios of a certain type of room on physiological stress, and the tool could say: “The likelihood of this design causing a negative physiological response is quite high.”

And if you make the ceilings higher, for example, you see that the predicted probability of a stress response goes down.

Of course, making such predictions would get more complex as we add in additional components such as the number and size of windows, or the behavioral context of the space.

Natalia: I think the key word for me is degrees of probability. When it comes to translational research, if you apply it ethically, you understand that it’s all about degrees of probability, not certainty.

Cleo: Absolutely. We definitely need to expand our base of knowledge – both qualitative and quantitative – before we can begin to make more specific predictions. Of course, there is a lot of incredible research looking at physiological stress, and other factors such as thermal comfort, construction hazards, indoor air quality, and sick building syndrome. But we are still in the early stages.

Is evidence-based design prescriptive?

Natalia: Many architects might see this as something prescriptive. There’s a whole spectrum of approaches to architecture, and different people argue for different styles. On the one hand, our brains are the product of thousands of years of evolution, and we are governed by biology.

On the other hand, we need a certain amount of exposure to novelty in our lives, we need experimentation to move forward. How much should we experiment when it comes to creating our environments and architectural features, and how much should we be prescriptive?

Cleo: I don’t think it needs to be one or the other, I think there is room for innovation and artistic expression within a prescriptive framework. I like to give the example of vehicle safety regulations which require cars to have seat belts, rear view mirrors and a whole host of other features, yet we see great variation in the way cars are designed.

Car designers are finding creative ways through user experience and safety requirements. Image: Oli Woodman

Interestingly, our preferences can, at times, be at odds with our neurophysiological responses. So what we need to think about is how to reconcile our design choices with our biological predispositions.I’m trying to isolate the architectural forms that support good health, while leaving the creative interpretation of these forms to architects.

While this may create practical design constraints, I don’t think it negates the architect’s creative freedom. In this way, I believe neuroarchitecture researchers and architects can come together to make both beautiful and healthy buildings.

We end up living in environments that are beyond the limits of our evolutionary adaptations.

Michal: Could you tell us about a place that you think is a good example of something that is in line with the principles we have been talking about?

Cleo: What comes to mind are the different cities that speak to the human scale. For example, Haussmann’s renovation of Paris, or Copenhagen. I think one of the reasons these cities appeal to me is that they incorporate a number of the features we are coming to associate with reduced stress, such as ornamentation, fractalization, and even the height of buildings differs from the skyscrapers of Toronto or Dubai.

Interestingly, when I lived in Copenhagen, one of my professors told me that the reason downtown Copenhagen is the height it is, is because it’s the highest they could build wooden fire ladders to reach.

Cities with human scale are better suited to our evolutionary, biological limits. Image: Darth Liu

I think this perhaps speaks to how we have, through advances in building techniques, begun to overcome the physical limitations that architects have historically experienced.

We now have reinforced concrete and steel, we can build bigger and taller, we can build glass buildings thanks to air conditioning. These advances have been quite rapid, and our biology may not be able to keep up with these changes, which means that we end up living in environments that are beyond the limits of our evolutionary adaptations.

Once again, it comes back to reconciling what we can do with what we should do – my research aims to bridge this divide and provide architects with the tools to create spaces that support public health.

Subscribe to Venetian Letter

You will receive our regular newsletter with blog posts, interviews, books and events on human-focused architecture and urban design.