Extreme Heat Increases the Risk of Heart Attacks

17th July 2025

2 minutes read

Extreme Heat Increases the Risk of Heart Attacks

With climate change triggering increasingly frequent and intense heatwaves worldwide, scientists and health professionals are sounding the alarm: extreme temperatures can have severe effects on the cardiovascular system, significantly raising the risk of heart attacks, especially among vulnerable populations.

Physiological impact of heat on the heart

When the body is exposed to extreme heat, it works hard to regulate its internal temperature. This is mainly achieved through sweating and the dilation of blood vessels. These mechanisms cause a drop in blood pressure and force the heart to pump faster to maintain adequate blood flow to the organs. While a healthy individual might tolerate this stress, for those with pre-existing cardiovascular conditions, it can trigger a heart attack.

Additionally, excessive sweating leads to dehydration, which can thicken the blood and increase the risk of clot formation — one of the main causes of myocardial infarction.

High-risk groups

Elderly people, individuals with chronic diseases (such as hypertension, diabetes, or coronary artery disease), young children, and workers exposed to extreme heat are particularly vulnerable. These groups have reduced thermoregulation abilities and are more sensitive to heat-related complications.

Scientific data and evidence

Numerous epidemiological studies have confirmed a strong correlation between heatwaves and increased hospital admissions for heart attacks. Research published in The Lancet Planetary Health found that a 1°C increase above the seasonal average temperature can raise the risk of serious cardiovascular events by 5 to 10%.

Data from several European countries, the United States, and Asia have shown spikes in cardiovascular mortality during heatwaves, especially when hot nighttime temperatures prevent the body from recovering.

Prevention and public health recommendations

To mitigate these risks, public health agencies recommend several simple yet crucial measures:

Drink water regularly, even without feeling thirsty.
Avoid strenuous physical activity outdoors during peak heat hours (11 a.m. to 5 p.m.).
Stay in cool or air-conditioned environments as much as possible.
Wear light, breathable clothing in bright colors.
Monitor signs of fatigue, dizziness, or chest pain.

At-risk individuals should consult their doctors to adjust medications during hot periods and never stop treatment without medical advice.

Extreme heat is not merely a seasonal discomfort — it is a serious public health concern. Understanding its impact on the heart and promoting targeted prevention strategies could help save lives, especially as global warming continues to amplify the frequency and intensity of heatwaves.