Heat and the Heart

Abstract

Globally, more people die from cardiovascular disease than any other cause. Extreme heat can have serious implications for heart health, especially in people with pre-existing cardiovascular conditions. In this review, we examined the relationship between heat and the leading causes of cardiovascular diseases as well as the proposed physiological mechanisms for the deleterious effect of heat on the heart. The body's response to high temperatures, including dehydration, increased metabolic demand, hypercoagulability, electrolyte imbalances, and systemic inflammatory response, can place a significant strain on the heart. Epidemiological studies showed that heat can result in ischemic heart disease, stroke, heart failure, and arrhythmia. However, targeted research is needed to understand the underlying mechanisms of hot temperatures on these main causes of cardiovascular disease. Meanwhile, the absence of clinical guidance on how to manage heart diseases during heat events highlights the need for cardiologists and other health professionals to lead the charge in addressing the critical relationship between a warming climate and health.

Keywords: CVD; Climate change; Heatwaves; Hot temperatures; cardiovascular.

Figure 1

Pathophysiological mechanism of the impact of heat on ischemic heart disease. Extreme heat triggers peripheral vasodilation and sweating to reduce core body temperature. This vasodilation and sweating leads to dehydration, which causes hemoconcentration and lethal electrolyte imbalance. Additionally, dehydration leads to tachycardia and sympathetic activation. This adaptation by the body in extreme temperatures can have devastating effects, particularly in individuals with pre-existing heart disease leading to demand ischemia or plaque rupture, causing myocardial infarction.