Barcelona faced record-breaking heat on June 28, 2025, with afternoon temperatures soaring past 35°C in the city’s historic quarter. For Montse Aguilar, a 51-year-old cleaning worker, the extreme weather proved fatal.

Montse began her shift at 2:30 p.m., working in the old town’s dense streets where heat and humidity were amplified by narrow alleys and heavy tourist traffic. She reportedly complained of chest tightness, muscle cramps, and back pain. Her supervisor advised her to rest and stay hydrated, but she chose to complete her shift.

That evening, Montse messaged a friend to say she had felt “like I was going to die” earlier that day. Minutes later, while having dinner with her elderly mother, she collapsed. Neighbors attempted resuscitation, but she could not be revived.

While the autopsy has yet to confirm the cause of death, her family believes she suffered heatstroke and is preparing to take legal action against both the private cleaning company and the city of Barcelona. The local government has denied wrongdoing but has opened an investigation into workplace conditions during the heatwave.

Medical experts emphasize that fatal heatstroke is a growing risk in urban centers, particularly for workers in outdoor or poorly ventilated environments. The body’s ability to regulate internal temperature can break down rapidly in such conditions, especially during physical exertion. Without timely intervention, hyperthermia can lead to multi-organ failure and death in a matter of hours.

“Heatstroke is not just discomfort — it’s a medical emergency,” warned a spokesperson from the Spanish Emergency Medical Association. Vulnerable groups include the elderly, children, and anyone working under the sun or in hot enclosed spaces.

Too Much of a Good Thing? Doctors Also Warn Against Overhydration During Heatwaves

As record temperatures sweep across Europe, public health campaigns continue to urge hydration. But doctors are also warning about a lesser-known risk: drinking too much water, too quickly.

According to Dr. Stephanie Widmer, a medical toxicologist and emergency physician quoted in Fréquence Médicale, overhydration — or water intoxication — can be just as dangerous as dehydration. While rare, it is most likely to occur during extreme heat when people chug large quantities of water in a short period of time.

“The symptoms can be subtle at first — nausea, disorientation, and fatigue,” Dr. Widmer explains. “But in serious cases, overhydration can cause brain swelling, leading to seizures, coma, or even death.”

The danger lies not just in how much water is consumed, but how fast. Drinking more than one liter per hour consistently over several hours can overwhelm the kidneys and disrupt the body’s sodium balance — a condition known as hyponatremia.

To stay safe, experts recommend:

• Drinking slowly and consistently throughout the day.
• Avoiding large amounts of water in short bursts (e.g., three glasses at once after hours without drinking).
• Limiting water intake to no more than one liter per hour.

In times of extreme heat, it’s crucial to find the right balance. “Hydration is vital, but moderation and timing matter just as much as quantity,” Dr. Widmer said.

As climate extremes become more frequent, both under- and over-hydration are emerging as serious public health risks. Montse Aguilar’s case is a tragic reminder that heat-related illness can strike quickly — and that both individuals and institutions must adapt to protect those most exposed.