Extreme Heat and Cold Now Trigger Deadly Heart Risks Worldwide

Rising extreme temperatures—both scorching heat and bitter cold—are placing growing strain on heart health worldwide. These dramatic shifts in weather patterns are now linked to a higher risk of heart attacks, strokes, and sudden cardiac death. Vulnerable groups, including older adults, pregnant people, and outdoor workers, face the greatest dangers.

Extreme heat disrupts the body’s ability to regulate blood pressure, often leading to hypotension and forcing the heart to work harder. Prolonged exposure can overwhelm the cardiovascular system, particularly in those with pre-existing conditions. Meanwhile, cold weather triggers vasoconstriction, raising blood pressure and increasing the heart’s workload through heightened nervous system activity.

The problem is worsening as heatwaves grow more frequent, intense, and prolonged. This shift reverses historical trends where cold weather posed the primary threat. At the same time, the healthcare sector itself contributes to the issue, accounting for roughly 8.5% of U.S. greenhouse gas emissions. Experts warn that addressing this crisis demands action on multiple fronts. Research must deepen understanding of temperature-related cardiac risks, while clinical practice needs stronger preventive measures. Public policy plays a key role, from ensuring affordable energy for cooling to expanding access to cooling centres. Transitioning healthcare toward low-carbon models could also help align patient care with environmental sustainability.

Without coordinated efforts, the cardiovascular toll of extreme temperatures will continue to climb. Immediate steps in policy, healthcare, and research are needed to protect at-risk populations and reduce long-term health impacts. The challenge requires balancing patient care with broader environmental responsibility.