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Extreme heat threatens health of old and young alike


Outdoor work, illness and advanced age are risk factors for ill-health in extreme heat events. Young children, too, are a vulnerable group when high temperatures are affecting ever more regions worldwide, a summary report from the University of Gothenburg shows.

The purpose of the report, in the area of occupational and environmental medicine, is to provide a concise summary of health effects related to heat.

The report describes the most disadvantaged populations in the world, regions where extreme heat prevails, and various future scenarios for global warming. The material was taken from reports and scientific publications from the years 2004–2022, with an emphasis on the past few years.

Anna-Carin Olin, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg,
Photo: Elin Lindström

Anna-Carin Olin, Professor of Occupational and Environmental Medicine at Sahlgrenska Academy, University of Gothenburg, is a member of the editorial committee responsible for the report.

“What’s most striking about the material is the scale of the problems — the fact that extreme heat affects so many people. And in a rising number of areas in the world, there’s a risk they’ll get so hot that people can’t live and work there,” she says.

Children especially vulnerable

The report describes “heat stress,” which arises when the body is exposed to such extreme heat that its impact on the heart and circulatory system cannot be kept at bay. In combination with the factors of outdoor work, illness, and/or old age, there are growing risks of low blood pressure and heat-related headaches, for example, and of heat stroke and death in more severe cases.

Children's vulnerability is also highlighted. Very young children have a small body volume in relation to their heat-exposed body surface, which makes them extra sensitive to heat stress and dehydration.

Overpopulated metropolitan environments in the hottest countries, where daytime heat is absorbed in streets and buildings, retained, and then slowly released at night, are tough places for children to live in. These “urban heat islands” provide no space for recovery from the heat.

“These conditions are especially harsh in developing countries, where they are often found in the poorer parts of large cities. There, opportunities to cool down are lacking. In these areas, where finding shelter is impossible, children are a particularly vulnerable group,” Olin says.

Problems in Sweden too

The populations that rising temperatures are going to affect most are in regions of the world that are already hot, where even tiny changes in temperature are set to have a serious impact on health. In Europe, increasing heat-related mortality is expected to be offset by declining cold-related mortality, although not in the longer term.

“We mustn’t forget that we’re vulnerable as well,” says Anna-Carin Olin. “Not least, that applies to elderly people who live alone or in care homes. For them, we don’t always have the preparedness to offer protection from high temperatures.”

Title: ”Extreme high temperatures — a threat to human health” – the report is available to download at