Heatwaves Kill Heart Patients: New Report Maps Seven-Times Risk and Life-Saving Heat Plans

Older adults living with heart disease face up to seven times the risk of dying during a heatwave compared with cooler conditions, and a major new report from the European Society of Cardiology argues that most of these deaths are preventable if health systems act before the hot weather arrives. The report, published in the European Heart Journal, brings together the existing evidence on how extreme heat affects people with cardiovascular disease and translates it into practical guidance for doctors, nurses, allied health professionals, hospital administrators and public health agencies. Its central message is stark: heat preparedness should not begin when a patient collapses in an emergency department during a heatwave, but much earlier, as part of routine, anticipatory cardiovascular care.

The physiological problem is well established but often underestimated. Extreme heat is not simply a matter of discomfort; it places considerable stress on the cardiovascular system. As ambient temperatures rise, the body must dissipate heat by increasing blood flow to the skin and by sweating, which raises heart rate and cardiac output while reducing blood pressure through vasodilation. For a healthy heart this is a manageable challenge, but for a heart weakened by failure, constrained by coronary disease, or destabilised by arrhythmia, the added workload can tip the balance toward decompensation, myocardial ischaemia, dangerous rhythm disturbances or death. Dehydration thickens the blood and increases the risk of clotting, while excessive fluid intake or impaired regulation can lead to overhydration and dangerous dilution of electrolytes. Medications that many cardiac patients take, including diuretics, beta-blockers, ACE inhibitors and other antihypertensives, can further complicate how the body copes with heat, affecting sweating, blood pressure regulation and fluid balance.

Dr Georgia Chaseling of the University of Sydney, an author of the report, explained the motivation behind the work. She noted that while researchers already understand that extreme heat increases the risk of illness and death in cardiovascular patients, understanding the problem is only the first step. Doctors and other healthcare professionals, she said, need practical guidance on what they can actually do to protect their patients. The report was written to translate the scientific evidence into usable advice covering the entire pathway of care: identifying vulnerable patients, preparing them for extreme heat, managing their medications, advising on hydration and cooling, monitoring them during hot weather, adapting cardiac rehabilitation and exercise, and continuing surveillance after a heatwave has passed.

A cornerstone of the report is the concept of the individual heat plan. Because vulnerability varies enormously from patient to patient, the authors argue that clinicians should know who is at risk before periods of extreme heat occur, discuss personalised heat-management plans with them, and consider how each person’s illness, medication regimen, hydration needs and living circumstances shape their risk. An elderly heart failure patient living alone on the top floor of an uninsulated apartment building faces a very different threat profile from a younger, fitter patient with well-controlled hypertension, and the plan must reflect that reality. The report frames this as anticipatory cardiovascular care, embedding heat risk into the same preventive framework already used for smoking, diet, blood pressure and cholesterol.

The recommendations extend well beyond the clinic. Extreme heat can sharply increase demand on emergency departments, hospitals, primary care services, home care and social services, and the report argues that health systems therefore need formal heat action plans, adequate surge capacity and resilient infrastructure. Hospitals should be prepared for waves of heat-related admissions, with staffing, bed capacity and cooling arrangements that can flex when temperatures spike. Proactive outreach is essential to reach vulnerable people who may be socially isolated or have limited access to cooling, since isolation itself is a known risk factor for heat deaths. Achieving this, the authors say, will require coordination between healthcare providers, emergency services, public health agencies and local authorities, so that warnings, cooling resources and clinical follow-up reach the people who need them most.

Some of the most concrete suggestions concern home-based care. The report details the need for proactive home healthcare during heatwaves, with visiting services monitoring patients and providing cooling resources such as fans, ensuring suitable storage for medications that may degrade in high temperatures, and watching for early signs of both dehydration and overhydration in vulnerable patients. These measures may sound modest, but they target precisely the window in which deterioration can be caught and reversed before it becomes an emergency admission or a fatality. The report’s authors present such interventions as part of a spectrum of preventable harm: with the right heat plans tailored to each patient, deaths that currently occur in heatwaves need not happen.

The report also provides population-specific recommendations that clinicians can apply directly. In patients with heart failure, clinicians should carefully monitor hydration, body weight, electrolytes and medication use, since the delicate fluid balance these patients maintain can be disrupted quickly by heat and sweating. In patients with arrhythmias, particular attention should be paid to changes in the body’s salt and mineral balance, hydration status, and symptoms such as palpitations, dizziness and excessive fatigue, all of which may signal that heat stress is destabilising the heart’s electrical system. For people with hypertension, home blood pressure monitoring and the prevention of heat-related hypotension and falls become particularly important, because vasodilation and medication effects can combine to drop blood pressure to dangerous levels, increasing the risk of syncope and injury.

For patients and their families, the report carries an equally important set of messages. Co-author Professor Philip Moons of the University of Leuven in Belgium emphasised that the aim is to make preparedness for extreme heat part of routine cardiovascular care, and that as heat extremes become more frequent and intense, no one should wait until a heatwave occurs to start thinking about how to protect patients. The most important message for families, he said, is that the cardiovascular risks associated with extreme heat are at least partly preventable. People with cardiovascular disease should recognise that hot weather may require changes to their usual routines, closer attention to hydration and cooling, and careful monitoring of blood pressure and heart rate. They should also know when symptoms such as dizziness, confusion, worsening breathlessness or palpitations require medical attention. Crucially, patients should not stop or change their cardiovascular medication on their own because of hot weather, a common and potentially dangerous mistake.

The report, published on behalf of the ESC’s Association of Cardiovascular Nursing & Allied Professions, the Association for Acute CardioVascular Care, the European Association of Preventive Cardiology, the Heart Failure Association and the European Heart Rhythm Association, together with the ESC Council on Hypertension, the ESC Council on Stroke and the ESC Working Group on Cardiovascular Pharmacotherapy, is candid about the limits of current knowledge. The authors say more research is needed on why some patients appear more vulnerable to heat than others, a question with direct clinical consequences for how heat plans are targeted. They also highlight a striking gap in the evidence base: most research on how heat affects common cardiovascular medications comes from studies conducted in young, healthy individuals, rather than the typical patients who actually take these drugs, people who are often older, frailer and living with multiple other health conditions. Filling these gaps, the authors argue, is essential if guidance is to keep pace with a warming climate.

What emerges from the report is a vision of climate-adapted cardiology in which extreme heat is treated as a clinical variable as routine as blood pressure or cholesterol. The stakes are enormous: heatwaves are becoming more frequent, more intense and longer-lasting across Europe and much of the world, and the population of older adults with cardiovascular disease continues to grow. The report’s authors make clear that the tools needed to save lives already exist, from fans and medication storage advice to hospital surge planning and personalised heat plans. What has been missing is the systematic integration of these tools into everyday cardiovascular practice. If the report’s recommendations are adopted, the next heatwave could find patients prepared, clinicians vigilant and health systems ready, rather than scrambling to respond once the deaths have already begun.

Subject of Research: Protecting people with cardiovascular disease from heat-related illness and death during heatwaves

Article Title: From distributing fans to preparing hospitals for heat surges: report shows how we must protect people living with heart disease in heatwaves

Article References: From distributing fans to preparing hospitals for heat surges: report shows how we must protect people living with heart disease in heatwaves. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: heatwaves, cardiovascular disease, European Society of Cardiology, European Heart Journal, heart failure, hypertension, arrhythmias, heat plans, hospital surge capacity, dehydration, home healthcare, climate change