The Heart Attack You Didn’t See Coming
Heart attacks spike during heatwaves, yet the connection between extreme heat and cardiovascular disease remains largely invisible in public health discourse. Death certificates rarely mention heat as a contributing factor, making it difficult to mobilize resources or implement protective measures.
The physiology is straightforward but deadly. When your body overheats, blood vessels dilate to help cool you down. This dilation drops blood pressure, forcing your heart to pump harder and faster to maintain circulation to vital organs. For healthy hearts, this represents manageable stress. For people with existing cardiovascular conditions, it can be catastrophic.
Across southern Europe last summer, researchers found that extreme heat was responsible for 68% of temperature-related deaths, with the vast majority occurring among people with pre-existing conditions pushed beyond their limits. These weren’t people exercising outdoors or working construction—they were in homes and hospitals, quietly succumbing to physiological strain.
Dr. Madeleine Thomson of Wellcome emphasizes that focusing solely on direct heat deaths misses the larger picture. “Extreme heat doesn’t just kill—it also increases the risk of heart disease, pregnancy complications, and poor mental health,” she explains.
The challenge extends beyond immediate cardiac events. Prolonged heat exposure can worsen underlying cardiovascular conditions, accelerate disease progression, and increase long-term mortality risk even for people who survive initial heat stress.
Vulnerable populations face compounded risks. Older adults, whose cardiovascular systems are already stressed, represent 85% of heat-related deaths. People taking certain medications—including common blood pressure and psychiatric drugs—face impaired temperature regulation. Those without access to air conditioning or adequate cooling have nowhere to escape when heat becomes dangerous.
Understanding these hidden cardiovascular impacts is crucial for developing effective heat action plans that protect the most vulnerable.