Dr Paulo Morgado is associate professor at the Institute of Geography and Spatial Planning of the University of Lisbon (Portugal). He studies smart cities and how city design affects the human brain and health.
We often talk about the physical health effects of extreme weather. How does it also affect stress and mental well-being in cities?
Many confounding factors, like noise, air pollution, aesthetics, openness, and street connectivity, can increase physiological load. We’ve measured these effects, finding that heat and environmental stressors can elevate heart rate, induce skin responses, and impair cognitive functions like attention, memory, decision-making, and increase anxiety and fatigue. We’re now moving beyond simple correlations to use new methods that help establish causal relationships.
Your research highlights green spaces as a way to reduce stress. How strong is the evidence that urban design can directly improve mental health?
Paulo Morgado: As you move around, you experience different microclimates. On one side of the street, you might be more exposed to the sun, while on the other, trees, shadows, and fewer cars or noise can create a contrasting environment. A key recommendation is that having more green spaces can have real beneficial effects on our overall well-being.
For instance, planting more trees has proven to generate immediate benefits. Spending a few minutes in a green space after exposure to traffic or noise can lower your heart rate and help you recover attention and reduce cognitive fatigue quickly.
However, it’s not just about adding more trees; the amount of greenery matters, but other factors, such as noise and crowding, come into play and can diminish these benefits. If green spaces are crowded or noisy, such as near airports with constant noise, the regenerative benefits are reduced. Therefore, specific areas require specific percentages and types of green to maximise these positive effects.
You also show that factors like density and crowding matter. How do features like busy streets or built-up areas influence how people feel?
Paulo Morgado: An overly busy street feels uncomfortable, triggering stress, and when you add noise to the mix, this creates a challenging environment. The core issue is that the current design doesn’t fully address the effects of crowding. By ‘design,’ I’m referring to how we define vibrancy, streets that attract people with shops and amenities and encourage walking. To make this work better, we need built-in escape zones and stronger connections between streets, so people can find moments of relief.
The same idea applies to climate challenges: the available data can help create climate shelters that support health and prevention. High density can work, but only if it includes clear routes and spaces for refuge.
How can city planners use this kind of research to make urban areas healthier and better prepared for extreme weather?
Paulo Morgado: Cities have historically been designed with a focus on form and functionality, often neglecting human needs. What we bring as a novel approach is evidence that combines subjective perceptions from surveys, interviews, and questionnaires with objective, measurable data from wearables.
This integration centres human experience, making people a key source of data for urban planning and design. It’s also about how people feel in these environments, which is crucial because exposure to certain urban settings significantly affects people’s health.
The World Health Organisation reports that exposure to several urban environmental factors (air pollution, noise, urban heat islands, chemicals, etc.) can increase the risk of depression, anxiety, sleep disorders, cardiovascular diseases, type 2 diabetes, and mental fatigue by over 20%. Thus, understanding and addressing these effects is essential for healthier urban development.
Many people see urban greenery as an obvious solution. What are its limits, and what else is needed?
Paulo Morgado: Green spaces offer multiple benefits beyond aesthetics, including noise buffering and climate change mitigation. They are recognised as nature-based solutions for extreme events like floods and heatwaves, and they improve air quality.
Aesthetic value also supports mental well-being, as noted research indicates that contact with nature enhances mental health. Green spaces within 300 to 500 meters of residential areas encourage walking and outdoor activity, promoting urban green therapy, stress recovery, and physical health by regulating metabolism and reducing fatigue. They boost mood through the release of endorphins and serotonin.
For urban planners and decision-makers, it’s now possible to identify stress-inducing routes and design cities with restorative features such as green corridors, climate shelters, and low-stress mobility networks. Building facades also impact stress levels; engaging facades with balconies and greenery can increase relaxation and attention, whereas dull facades raise heart rate and stress. Behavioural responses, like walking speed, reflect cognitive load.
Architectural design, therefore, influences emotional well-being, and simple measures like removing graffiti or reducing noise can significantly improve urban navigation and engagement.
What should European policymakers do to build cities that are more resilient, less stressful and better for your health?
Paulo Morgado: There is still work to be done. While we have some evidence, it primarily serves as a proof of concept. We need to scale up our efforts and begin measuring the impact factors.
Establishing a data pipeline is essential for informing policies, making decisions, and implementing actions. This approach aims to transfer knowledge into real-world applications, similar to biological data used in smart cities or digital twins. We must incorporate these data at a large scale, integrating physiological and behavioural information into urban monitoring systems.
Moving from general perceptions or averages to evidence-based decisions will help target the most vulnerable populations, those most affected by socio-economic factors and climate change.
Additionally, understanding how these factors influence mental health is crucial. We have observed overlaps between areas where people experience or are diagnosed with issues like depression or anxiety and regions exposed to extreme events. We must address these inequalities and incorporate health data into planning decisions.
City design should reflect how people perceive their environment. On top of this, we need new regulations, harmonised data, and better access to health equipment and infrastructure. All these elements are necessary to create healthier cities.
Is there anything you would like to add?
Paulo Morgado: Another thing is that we need more research to explore how artificial intelligence can accurately predict the future impacts of urban environments on us.
The main thing is awareness, the knowledge that all citizens can use to influence policymakers and decision makers, reminding them to care about the urban environment we live in.
During COVID-19, many struggled with mental health issues due to a lack of outdoor socialisation. Nature and outdoor activities are essential for mental well-being, reducing reliance on medication like antidepressants. Connecting with nature and others can improve mental health naturally. Several projects, including our own studies, show that outdoor exposure can lower cognitive stress and improve overall well-being.