Just as parts of Europe experienced unprecedented heat last month, the United States is bracing itself for dangerously high temperatures, with forecasts for record-breaking warmth coinciding with the July 4 holiday. Major cities in the central and eastern regions of the country are under heat advisories, projecting sizzling temperatures that could reach between 100 and 115 degrees Fahrenheit (37.8-46.1 °C).

Meanwhile, Europe grappled with its own extremes, reporting soaring temperatures across France, Germany, Spain, the UK, and more. Germany’s weather service noted that the record-setting heat was not only remarkable for its intensity but also for its duration, marking one of the earliest heat waves of the year.

Such relentless heat, with daytime temperatures consistently surpassing 30 degrees Celsius (86 Fahrenheit) and stifling nights lingering above 20 C, imposes a significant burden on human health, particularly affecting vulnerable groups like the elderly and those with chronic conditions.

How do humans cope with extreme heat?

According to Dr. Claudia Traidl-Hoffmann, an expert in environmental medicine, the human body is capable of adapting to heat better than most people realize. "The ability to cope with heat improves in individuals who are regularly exposed to high temperatures," she explains. Traidl-Hoffmann serves as the director of the Institute of Environmental Medicine at the University of Augsburg and treats patients affected by climate-related health issues.

While individuals in hotter climates tend to have more developed physiological adaptations, Dr. Traidl-Hoffmann warns that the escalating frequency of heat waves poses an unprecedented challenge. “Adaptation to these fast changes won’t take years,” she argues, “but centuries.” This isn't merely a footnote—it's indicative of a far more alarming trend regarding climate change and public health.

The human body's response to extreme temperatures

As temperatures rise, the body kicks into gear with mechanisms aimed at maintaining homeostasis. "When the thermometer reads above 23 C (73.4 F), physiological processes start working to cool the body," she explains. Blood vessels expand and sweating increases, both crucial for regulating core body temperature.

However, failure of these processes can have dire consequences, as the body may slide into a state of crisis leading to severe health issues including cardiovascular problems and organ failure—especially critical when core temperatures exceed 42 degrees Celsius (107.6 F), which can result in fatal outcomes without prompt intervention.

Moreover, prolonged exposure to extreme heat can wreak havoc on the respiratory system. Traidl-Hoffmann points out that although the underlying mechanisms are still not fully understood, research suggests that inhaling hot air could spark inflammatory responses in the lungs, making them more susceptible to infections.

“The lungs become inflamed more easily and more vulnerable to infections,” she notes, highlighting a critical area for health concerns during heat events.

What proactive measures to consider during heat waves?

Dr. Traidl-Hoffmann emphasizes the need for preventive thinking regarding heat management. Many wait until heat becomes unbearable to take action, by which time infrastructure like railways is already buckling and emergency services are stretched thin.

Instead, she advises individuals to plan ahead during the winter months, ensuring existing medical conditions are managed before summer's heat. This includes reviewing any medications with healthcare providers to mitigate heat-related reactions, especially for those with chronic illnesses.

Moreover, she highlights the importance of early treatment for chronic conditions such as eczema, which can flare up under heat stress. When the heat reaches its peak, Traidl-Hoffmann suggests staying hydrated, maintaining a light diet focused on plant-based foods, and minimizing the intake of caffeine and alcohol—both of which can exacerbate the body’s temperature regulation challenges.

Can humanity withstand the climate crisis?

As night temperatures rise, so too does the risk that many will suffer from inadequate sleep, which could lead to physiological decompensation—the body's inability to effectively manage stressors stemming from heat. The speed of climate change means that how people adapt varies drastically. Traidl-Hoffmann likens individual resilience to a barrel; for those who are older, have chronic illnesses, or are on medications, the “barrel” fills up faster during heat episodes.

Younger individuals in good health typically handle heat better, but this too has its limits. “The rapid increase in extreme heat events is exceeding what both humans and ecosystems can manage,” she cautions, a reflection of a broader, more serious issue regarding our changing environment.

This article was originally written in German.