Extreme Heat: An Underestimated Threat to Health?

By Ana Espino | Published on June 09, 2026 | 4 min read

More frequent heatwaves, record-breaking temperatures, prolonged periods of extreme heat… Climate change is gradually turning extreme heat into a major public health challenge. While heatstroke is one of the most visible consequences of these events, the health effects of high temperatures extend far beyond acute heat-related illnesses. In reality, extreme heat influences numerous chronic diseases, increases mortality, and places growing pressure on healthcare systems.

This issue is particularly concerning in Africa, where many populations are already exposed to high temperatures, work outdoors, and may have limited access to water, electricity, or effective cooling solutions. Yet the health impacts of heat exposure remain insufficiently recognized in clinical practice. A review published in the African Journal of Primary Health Care & Family Medicine examines the effects of extreme heat and the measures needed to protect the most vulnerable populations.


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When Heat Exceeds the Body’s Capacity to Cope

The authors remind us that the human body relies on several mechanisms to regulate temperature, including sweating and increased blood flow to the skin. However, when temperatures become excessively high—particularly when combined with high humidity—these mechanisms can be overwhelmed. Heat then accumulates within the body, triggering a cascade of physiological reactions that may lead to cellular damage, systemic inflammation, and, in the most severe cases, multiorgan failure.

The mildest forms of heat-related illness include cramps, edema, and heat exhaustion. At the extreme end of the spectrum, heatstroke is a medical emergency characterized by a core body temperature above 40°C (104°F) accompanied by neurological symptoms such as confusion, seizures, or coma.

However, the consequences of extreme heat are not limited to heat emergencies. The reviewed data show that periods of intense heat worsen numerous chronic diseases. Cardiovascular risk rises significantly, with increased rates of arrhythmias, heart failure, and coronary events. One meta-analysis cited by the authors reported a 2.1% increase in cardiovascular mortality for every 1°C rise in ambient temperature.

Respiratory disorders, acute kidney injury, and metabolic decompensation are also more common during heatwaves. Outdoor workers are among the populations most affected by heat-related kidney damage.


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Particularly Vulnerable Populations

The article also highlights inequalities in vulnerability to heat exposure. Infants, older adults, pregnant women, individuals with chronic illnesses, and outdoor workers face a higher risk of complications.

Among pregnant women, several studies have identified an association between extreme heat exposure and increased risks of preterm birth, stillbirth, gestational diabetes, and hypertensive disorders of pregnancy. Newborns are also particularly vulnerable due to their immature thermoregulatory systems.

The authors further emphasize less visible but equally important consequences of prolonged heat exposure. Heatwaves can contribute to sleep disturbances, irritability, reduced concentration, and worsening of certain psychiatric disorders. Several studies have also reported increases in aggressive behavior and suicide risk during periods of extreme temperatures.


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What If Prevention Became Just as Important as Treatment?

This review highlights that the health consequences of heatwaves extend far beyond the risk of heatstroke alone. Extreme temperatures affect virtually every organ system, exacerbate numerous chronic diseases, and disproportionately impact populations that are already vulnerable.

The authors stress the central role of primary healthcare providers in the early identification of at-risk individuals, treatment adjustment, education on hydration, and the implementation of community-based prevention strategies. They also remind clinicians that rapid cooling remains the cornerstone of heatstroke management, while conventional antipyretic medications are ineffective in this setting.

Although this article is a narrative review rather than an interventional study, it underscores the urgent need to integrate heat-related risks into public health policies. As episodes of extreme heat become increasingly frequent due to climate change, strengthening the resilience of healthcare systems and protecting vulnerable populations may become one of the major public health challenges of the coming decades.


About the author – Ana Espino
PhD in Immunology, specialized in Virology  
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions.