Snapshot: 'Heat and Health in the WHO European Region' (2020)

Heat and Health report jacket

"We need to proactively protect people from dangerous heat via Heat-Health Action Plans (HHAPs). Fortunately, the number and reach of HHAPs is increasing in Europe, but there is still a lot countries without a plan or with very incomplete ones; there is a lot of ground to cover"

Climate change - Heat and health in the WHO European Region: updated evidence for effective prevention (2020) is co-produced by Gerardo Sanchez Martinez (Spain, 2005/07). The report provides a comprehensive and impactful account of recent epidemiological and environmental research in the field, and lessons learnt from practical implementations. In this Snapshot, Gerardo discusses the implications of the report and identifies areas for future actions and research.


The relationship between heat and health

Gerardo Sanchez MartinezWe typically associate heat with positive experiences like summer holidays and sunny days; but excessive heat, of the kind we see during heat waves, can be very dangerous. That is particularly the case for the elderly, people with chronic illnesses or disabilities, those with heart conditions, respiratory conditions, infants and pregnant women. Even healthier people, like recreational athletes and outdoor workers, can potentially suffer heat exhaustion or a heat stroke during a heat wave if they do not exercise caution. Every year, people in Europe die prematurely because of heat, particularly those who are vulnerable and cannot ensure adequate thermal comfort where they live. Moreover, climate change is making heat waves longer, more frequent and more intense. Adding that to the ageing of our populations and increasing rates of urbanization (which facilitates overheating), we are facing seriously increased risks to health from heat.

We need to proactively protect people from dangerous heat via Heat-Health Action Plans (HHAPs). Rather than simply issuing warnings via your mobile phone, TV or web, these plans must be comprehensive and address all aspects related to heat response, including forecasts, early warnings, coordination of stakeholders, communications, vulnerable groups. But they also need to promote systemic action, making our cities less prone to overheating and less dependent on carbon-intensive solutions like air conditioning. Fortunately, the number and reach of HHAPs is increasing in Europe, but there is still a lot countries without a plan or with very incomplete ones; there is a lot of ground to cover.

Priority areas identified in the report

Urban planning is fundamental to protect the health of local populations from heat in an equitable and sustainable way. We know that several types of urban planning interventions are effective in reducing dangerous exposures to heat, like increasing green spaces within urban centers, and various types of physical retrofitting of the form, composition and functionality of buildings and urban canyons. Overheating can be reduced by increasing the reflectivity of roofs, facades and pavements, by increasing the availability and accessibility of water bodies, and by creating wind corridors where possible. Obviously, the modification of the urban landscape is neither an immediate nor an easy undertaking, but they can offer many additional cobenefits – for instance, green spaces offer plenty of health benefits beyond protection from heat. However, these types of urban planning interventions as related to heat protection are infrequent, and health authorities do not have effective tools for inter sectoral action so that they could successfully mainstream health protection considerations into urban planning and management.

Finding effective governance arrangements to further the reach and protection of HHAPs is also important, and there is room for improvement via a stronger involvement of local actors and authorities.

But from all the difficult issues we have explored in our report, one of the trickiest and one that demands urgent discussion is the role of air conditioning, and more generally summertime energy poverty. The ability to keep your home acceptably cool during summer is highly related to whether you can afford cooling solutions, including the installation, maintenance and electricity consumed by AC. At the same time, a massive deployment of private AC units like what we are seeing globally has immense drawbacks in terms of carbon emissions, pollution, peak energy demand, risks of blackouts, and thermal equity. We need to ensure that those who need it most do actually have access to the benefits of cooling (including AC) while increasing the sustainability requirements of AC units and gradually abandoning our societal dependence on this single technological solution. 

Knowledge gaps

It is surprising how little we know about some things that could be regarded as basic in terms of health protection from heat. For instance, the evidence is inconsistent regarding the thermal comfort needs of various vulnerable groups, such as the elderly, as studies on thermal comfort are largely conducted on healthy and working populations. We do not have good empirical evidence of how outdoor temperatures affect indoor temperatures in a city in real life, since most studies are based on computer models rather than actual measurements. We have poor data on the real-time correlation between outdoor temperatures and indoor temperatures in residential settings, and that bodes ill for good prevention, since most people spend most of their time indoors, and vulnerable groups even more so.

In terms of communication, HHAPs rely crucially on vulnerable individuals and their networks taking action to protect themselves and/or their contacts, and evidence shows relatively good awareness on how to do so. However, there is a systematic underestimation of the health risks of heat by the general public and by vulnerable individuals, and, partly as a result, heat continues to cause illness, hospital admissions and premature deaths. We need to understand better how we should communicate in order to change the “risk signature” (i.e. the risk perception) of heat.

Also important, there are two very promising lines of research which are technology-based. The first one is on personal cooling devices. These include cooling air sleeves, cooling seats, cooling garments, desktop-based ventilation devices, etc. and could help us provide additional and personalized cooling protection options to those who need them most. The second concerns phase changing materials which can change their status (e.g. from solid to liquid), absorbing or releasing heat in the process. Incorporated into walls, floors and ceilings they can be used to improve thermal comfort indoors while reducing energy consumption, and they can be used for cooling purposes.

Fulbright experiences

I had had some training in environmental health before my Fulbright experience, but it was during my two Fulbrighter years - funded by the regional government of Madrid - at the Boston University School of Public Health that I decided to focus professionally on this. Being a Fulbright scholar opened me every door I knocked on and allowed me to meet the best in the field, to collaborate with them in research projects and in publications. It also helped me get paid internships during my Masters and to land relevant jobs thereafter. It was because I had the financial and institutional cover of the Fulbright programme that I could focus exclusively on the topic and dive deep into it. That helped me set a solid foundation of scientific methods that I have been using extensively since.


I am a Public Health specialist, focusing on the health impacts of climate variability and change, and more generally environmental risks to health. I have worked at the UNEP-DTU partnership, the World Health Organization and the World Bank, and lived in the USA, Japan, Peru and Germany. I hold a PhD in Economics, a Master in Public Health from Boston University (Fulbright 05-07), and an MSc in Environmental Risks. Find out more

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