Heat waves threaten health of both young and old

Heat waves threaten health of both young and old Andrew Zinin Lead Editor A brutal heat wave blanketing much of Europe has prompted reminders that extreme heat poses a particular threat to the health of children and the elderly. Public health messaging usually focuses on the elderly. However, the deaths of two children inside a car in France on Monday was a tragic reminder that the very young are also at risk. Scientists have said that human-caused climate change will make heat waves more frequent, intense and longer—such as the long week ahead of sweltering conditions forecast in Europe. Forecasters warned this week could rival a 2003 heat wave that claimed an estimated 70,000 lives across the continent. When temperatures soar, both the old and young are less able to regulate their body heat, sweat less, and tend to rely on others to take care of them. Heat waves "disproportionately" affect infants under 1 year old and people over 65 years, according to the 2026 Europe report of The Lancet Countdown on health and climate change. Heat wave exposure for elderly people soared by 266% during 2015–2024 compared with 1991–2000, according to the report. For infants, the rate rose by 121%. French epidemiologist Noemie Letellier told AFP that elderly people face the worst consequences of extreme heat because of "physiological limitations as well as different social factors, such as precariousness, isolation and dependency." Jacques Boddaert, the head of the geriatric department at the Pitie-Salpetriere University Hospital in Paris, said there were several factors that transform heat into "a real ordeal for these patients." One is that, as people get older, it becomes harder for their bodies to control their temperature. "The sensation of thirst also diminishes, and they react later to signs of dehydration," Boddaert said. Chronic illnesses that are more common in the elderly can make extreme heat more of a risk. Some drugs, such as those people take for heart conditions, include diuretics that can pose health problems during extreme heat. And if the people taking care of the elderly happen to be on holiday—which can happen over summer—the situation "can become very dangerous," Boddaert warned. But not all elderly people are the same, Letellier pointed out. Some may be enduring economic hardship, chronic illness, disability or be isolated from others. Elderly women, who tend to live alone, also have "more limited resources" than men, which can put them further at risk, Letellier said. Pregnancy risks While it is rarer for the death of young children to be directly attributable to high temperatures, extreme heat can contribute to numerous health problems. It can also cause issues for pregnant women. Some of the "most notable are increased risks of adverse birth outcomes, including preterm birth and low birth weight," according to a review of the evidence published in the Journal of Climate Change and Health in 2024. "Extreme heat exposure was also associated with increased rates among children of emergency department visits, asthma exacerbations, heat illness, and impaired school performance," it added. A Climate Central report warned last year that "climate change at least doubled the average annual number of pregnancy heat-risk days experienced during the past five years" across more than 200 countries. Heather Massey, associate professor in extreme environments and physiology at the University of Portsmouth in the UK, advised people to drink plenty of water and limit their exposure to the hottest part of the day. "Keeping indoor spaces cool by closing curtains or blinds during the day and opening windows at night can help reduce heat buildup," she said. Key concepts effects of climate changehazardshuman environmental safetyExtreme HeatMedical physics & public health© 2026 AFP