Effects of extreme heat on physiology, morbidity, and mortality under climate change: mechanisms and clinical implications

Climate change is escalating the frequency and severity of extreme heat events, significantly augmenting disease burden through heat exposure. However, understanding of the underlying mechanisms remains insufficient, hindering the development of targeted interventions for heat related illnesses. This review summarizes the multifaceted mechanisms by which heat exposure induces systemic and organ specific damage. It elucidates how heat stress not only triggers systemic physiological dysfunction but also exacerbates specific organ injuries, thereby increasing morbidity and mortality risks across populations. These mechanisms drive shifts in disease profiles toward acute heat related illnesses, cardiovascular diseases, renal disorders, and other conditions, particularly affecting vulnerable groups. Susceptibility to heat exposure spans the entire life course, from prenatal stages to old age, and is amplified by socioeconomic disparities. The review proposes initiatives to reduce negative health outcomes and advocates for the integration of heat exposure into clinical practice guidelines, to safeguard public health in an era of unprecedented thermal challenges.