Why does heat hit the heart so hard?

When temperatures soar, the cardiovascular system has to work harder to keep the body cool. For people living with heart disease, that extra strain can tip a stable condition into a medical emergency. The report's core argument is that extreme heat must become part of routine cardiovascular disease prevention and management — not something addressed only once a crisis is underway.

"Heat preparedness should not begin when a patient presents to an emergency department during a heat wave," Chaseling explained. "It should start much earlier, as part of anticipatory cardiovascular care."

That means knowing who is vulnerable before hot weather arrives, discussing individual heat-management plans with them, and considering how their illness, medication, hydration needs and living circumstances may influence their risk.

Are recommendations different for specific conditions?

Yes. The report tailors advice to different cardiovascular populations:

• Heart failure: clinicians should monitor hydration, weight, electrolytes and medication use carefully.
• Arrhythmias: pay particular attention to changes in the body's salt and mineral balance, hydration, and symptoms such as palpitations, dizziness and excessive fatigue.
• Hypertension: home blood pressure monitoring becomes especially important, along with preventing heat-related low blood pressure and falls.

What about health systems?

The authors warn that extreme heat can increase demand on emergency departments, hospitals, primary care, home care and social services. Health systems therefore need heat action plans, adequate surge capacity and resilient infrastructure.

Reaching vulnerable people who may be socially isolated or lack access to cooling requires proactive outreach. That, in turn, demands coordination between health care providers, emergency services, public health agencies and local authorities.

What should patients themselves do?

Co-author Philip Moons, a professor at the University of Leuven in Belgium, framed the message for patients and families: the cardiovascular risks of extreme heat are "at least partly, preventable."

"Hot weather may require changes in their usual routines and closer attention to hydration and cooling, and to blood pressure and heart rate," Moons said. Patients should also learn when symptoms such as dizziness, confusion, worsening breathlessness or palpitations require medical attention.

One warning stands out: patients should not stop or change their cardiovascular medication on their own because of hot weather.

What are the limitations?

The authors acknowledge significant gaps in the evidence. Researchers still do not fully understand why some patients appear more vulnerable to heat than others. And most of what is known about how heat affects common medications comes from studies in young, healthy individuals — not the older, frailer patients with multiple health conditions who typically take these drugs.

The full statement, "Reducing the burden of heat-related impacts on cardiovascular health," appears in the European Heart Journal (2026), DOI: 10.1093/eurheartj/ehag657. As heat extremes become more frequent and intense, the report's authors argue, waiting for the next heat wave to start planning is no longer an option.