Alcohol does not significantly increase dehydration risk, says senior doctor

As Denmark braces for soaring temperatures and festival season peaks, a senior doctor has dismissed the idea that alcohol alone leads to dangerous dehydration in the heat.

Peter Højholt Holland-Fischer, chief physician at Aalborg University Hospital, told DR that the belief alcohol causes significant fluid loss is a myth. While it may increase urination, the effect is minimal—studies show only a temporary rise in urine output of 0.5–1.5 percent.

“Alcohol is not diuretic to a practically meaningful degree. Yes, you urinate more, but that’s not surprising if you’ve just had three large beers,” he said.

The real risk, he warned, lies in poor judgment. Alcohol impairs the ability to recognize heatstroke or dehydration symptoms, such as chills—a paradoxical sign of overheating. It also raises the likelihood of accidents, including drowning, as intoxicated individuals may misjudge swimming conditions.

“If you’re drunk and think, ‘I’m cold, I’ll warm up,’ or ‘I’ll cool off with a swim,’ that’s a recipe for disaster,” Holland-Fischer said.

His advice for festivalgoers: moderate drinking, stay cool, hydrate with non-alcoholic fluids, and look out for one another.