Swedish lifesaving society warns against sudden cold-water immersion during heatwave

Sweden’s Lifesaving Society has urged people to avoid diving or jumping into cold water during the ongoing European heatwave, following multiple drowning deaths in France and the UK linked to the sudden temperature contrast.

Mikael Olausson, a spokesperson for the Swedish Lifesaving Society, told public broadcaster SVT that plunging into cold water while overheated can trigger a deadly physiological reaction. “Blood vessels constrict sharply, creating pressure throughout the body that forces breathing upward into the throat,” he explained. “This leads to rapid, uncontrollable gasps—risking fluid inhalation and drowning.”

Olausson emphasized that the primary danger is not prolonged hypothermia but immediate cold shock, which can overwhelm even strong swimmers. “People forget the water may still be 10–12°C,” he said. “Most of these incidents aren’t from gradual cooling—they’re from that first, unexpected jolt.”

The warning comes as record temperatures near 40°C grip parts of Europe, coinciding with a seasonal spike in drownings as more people seek relief in lakes, rivers, and coastal waters. The society advises testing water temperature gradually before full immersion and avoiding sudden entry when the body is overheated.