Over 10,000 died in Europe’s June heatwave

More than 10,000 excess deaths were recorded across the 27 EU countries during the week of 22–28 June, as a heatwave peaked in Spain, France, and the UK, according to EuroMomo data cited by Danish news agency Ritzau. Over 9,000 of the deaths involved people aged 65 or older.

Heat-related fatalities do not stem from a failure of the body’s temperature regulation, which humans handle well, but from the extreme strain extreme heat places on the cardiovascular system, says heat expert Jacob Feder Piil, a researcher in human heat tolerance. The heart must pump additional blood to the skin to enable sweating, a cooling mechanism that becomes difficult for those with pre-existing heart conditions—particularly the elderly and frail.

As core body temperature rises despite these efforts, early symptoms include dizziness and discomfort. If unchecked, this can progress to heatstroke, loss of consciousness, and organ damage as blood supply falters. Dehydration, another major risk, thickens the blood, further stressing the heart and impairing the body’s ability to sweat and cool itself. Without rapid cooling and fluid replacement, heatstroke can be fatal within a short time, Piil warns.

Healthy individuals are less vulnerable, as their cardiovascular systems can better handle the increased demand. Piil advises seeking shade, drinking plenty of fluids, wearing light clothing, and monitoring urine colour—dark urine signals dehydration. Physical exertion should be minimised, as it generates additional body heat. Allowing sweat to evaporate, rather than wiping it away, enhances cooling, as does contact with cold surfaces or water.