WHO warns extreme heat heightens heart and lung risks, urges vigilance

Rising heat waves across the world are increasing health risks, with the World Health Organisation (WHO) warning that extreme temperatures can be especially dangerous for people living with cardiovascular and respiratory diseases.

The warning comes amid growing concern over the impact of climate change and recent heat‑related tragedies, including the death of a three‑year‑old child in Europe during an intense heat episode that underscored the dangers of prolonged exposure to extreme temperatures.

Earlier this week, a three‑year‑old boy died in a suburb of Paris after becoming trapped inside a car when the child lock engaged. In a separate incident, the bodies of two children aged two and four were found inside their family’s car in a residential parking area.

French authorities say heat‑related deaths during the ongoing heatwave have risen to four children, while more than 55 drowning incidents have also been reported. The extreme temperatures affecting Europe are expected to move eastward, exposing nearly 150 million people to temperatures above 35°C.

According to the WHO, heat and air pollution can have a combined effect that puts additional pressure on the body, making health impacts more rapid and severe. People with heart disease may struggle to regulate body temperature as the heart works harder to cool the body, while those with lung conditions can experience worsening breathing problems as hot weather combines with poor air quality.

“Heat can make people seriously ill. Knowing the signs saves lives,” the WHO said.

Health experts warn that early signs of heat‑related illness should not be ignored. Symptoms include headache, dizziness, nausea, muscle cramps, heart palpitations, excessive sweating, unusual tiredness and shortness of breath. If untreated, heat stress can progress to confusion, agitation, collapse, seizures and reduced responsiveness, signs that require urgent medical attention.

The WHO recommends slowing down or stopping physical activity during extreme heat, moving to shaded or cooled areas, and drinking water regularly, even before feeling thirsty. People with heart and lung conditions are advised to avoid outdoor activities during peak daytime temperatures and closely monitor air quality levels.

The agency also urges the public to check weather forecasts, remain indoors where possible during heat alerts, and keep medications accessible, particularly for those managing chronic illnesses.

“If someone near you appears unwell, do not leave them alone. Move them to a cooling area immediately and seek first aid or emergency assistance,” the WHO advised.

The recommendations form part of WHO’s broader Beat the Heat initiative, which seeks to protect communities, workers, and people attending mass gatherings and sports events from the growing health risks associated with extreme heat, air pollution, and solar radiation.

As heat waves become more frequent and intense, health officials say public awareness, early action, and targeted protection for vulnerable groups will be critical to preventing illness and saving lives.

People living with cardiovascular disease and lung conditions are more vulnerable during heat waves because extreme heat places extra strain on organs already under pressure.

For people with cardiovascular disease, the body tries to cool itself by sending more blood to the skin and increasing sweating. This forces the heart to work harder and can lead to dehydration, lower blood pressure, irregular heartbeat, chest pain, worsening heart failure, or even heart attacks.

For people with lung diseases, hot air and air pollution can irritate the airways and make breathing more difficult. Heat can increase ground‑level pollutants and trap dirty air, reducing oxygen intake and triggering flare‑ups, coughing, wheezing, and severe breathing distress.

According to the WHO, when extreme heat combines with air pollution, the effects can become faster and more severe, increasing the risk of hospitalisation and death among vulnerable groups.

Extreme heat is being reported across several parts of the world, with Europe currently among the hardest‑hit regions, recording repeated heat waves, temperatures above 40°C, and rising heat‑related deaths.

The WHO notes that Europe is now the fastest‑warming region globally, with more than 200,000 heat‑related deaths reported in the last four years alone.

In Africa, extreme heat is increasingly affecting the Sahel, North Africa, and the Horn of Africa, where prolonged hot spells and climate extremes are becoming more frequent. Studies show Africa’s heat stress season has expanded significantly in recent decades.

In Kenya, extreme heat has increasingly been reported in arid and semi‑arid counties, including Turkana, Garissa, Mandera, Wajir, Marsabit, and parts of coastal Kenya, with health experts warning of growing risks of dehydration, heat stress, and worsening heart and lung conditions as temperatures rise.