With global temperatures rising and heatwaves becoming more frequent and intense, the impact on public health is a growing concern. A new scientific statement from the European Society of Cardiology (ESC) and several of its constituent bodies highlights the significant risk that extreme heat poses to cardiovascular health, particularly for the elderly and individuals with pre-existing cardiovascular disease (CVD).¹
The statement reviews epidemiological data, noting the substantial mortality from events like the 2022 European heatwave, which caused over 60,000 deaths.² It reiterates that individuals with pre-existing heart conditions face a markedly higher risk of heat-related mortality. A meta-analysis cited in the statement found that each 1°C increase above a location's optimal temperature threshold is associated with a 2.1% rise in all-cause CVD mortality.
Physiologically, heat exposure triggers thermoregulatory responses, including cutaneous vasodilation and sweating, to dissipate body heat. These responses place considerable strain on the cardiovascular system by increasing heart rate and cardiac output to maintain blood pressure. Dehydration from sweating can further exacerbate this strain by reducing plasma volume. In older adults and those with CVD, these adaptive responses are often blunted, increasing their vulnerability.
The statement details several mechanisms through which heat can precipitate adverse cardiovascular events. The increased myocardial oxygen demand, coupled with potential hypovolaemia and impaired coronary vasodilation in patients with CVD, can lead to a demand-supply mismatch, resulting in myocardial ischaemia. Furthermore, heat exposure can lead to dehydration and electrolyte imbalances, which may trigger arrhythmias. The authors also discuss how heat can promote a pro-inflammatory and pro-thrombotic state, with increased levels of inflammatory markers like interleukin-6 and potential for coagulation dysregulation, particularly in severe cases like heatstroke.
The authors state that their scientific statement provides a “comprehensive discussion on the epidemiological evidence of heat-related CVD, the human physiological responses to hot environments, the impact of heat on cardiovascular health, and the relative impact of social inequalities.”¹ The document also underscores the role of health and social inequities, such as low income and poor housing, in exacerbating heat-related health risks.
Looking forward, the ESC task force calls for an urgent research agenda to fill critical knowledge gaps. Key priorities include generating robust evidence on the specific physiological factors predisposing patients with CVD to heat-related events, developing effective and targeted interventions to mitigate these risks, and creating strategies to reduce health inequities and improve access to care in vulnerable populations, particularly in low-to-middle-income countries.
1. Chaseling GK, Uchmanowicz I, Bäck M, et al. Heat extremes and cardiovascular diseases: a scientific statement of the Association of Cardiovascular Nursing & Allied Professions, Association for Acute Cardiovascular Care, European Association of Preventive Cardiology, Heart Failure Association, European Heart Rhythm Association of the ESC, the ESC Council on Hypertension, the ESC Council on Stroke, and the ESC Working Group on Cardiovascular Pharmacotherapy. Eur Heart J. 2025;46(30):2950-2958. https://doi.org/10.1093/eurheartj/ehaf326
2. Ballester J, Quijal-Zamorano M, Méndez Turrubiates RF, et al. Heat-related mortality in Europe during the summer of 2022. Nat Med. 2023;29:1857–66. https://doi.org/10.1038/s41591-023-02419-z
This study was supported in part by the grant PNRR-P8-Age-it project PE0000015, CUP C13C22000660001.
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