Extreme heat and humidity strain the heart and increase the risk of dehydration and heat-related illness [1].

These physiological responses matter because the body's inability to dissipate heat can lead to systemic failure. When temperatures rise, the cardiovascular system must work harder to cool the skin, which can jeopardize overall stability in vulnerable populations [1, 2].

Health experts and medical researchers said that high heat and humidity reduce the body’s ability to dissipate heat [1, 2]. This failure in thermoregulation leads to cardiovascular strain, and significant fluid loss [1, 2].

Beyond the heart, the effects of extreme temperature exposure extend to other critical systems. Research indicates that such conditions can impair brain function and kidney function [1, 3]. The kidneys may struggle to maintain fluid balance as the body prioritizes cooling and hydration loss increases [2].

Exposure to these conditions occurs in any location where people face elevated outdoor temperatures and humidity [1, 3]. This is most common during summer heatwaves, where the combination of heat and moisture prevents sweat from evaporating effectively [1, 2].

Medical professionals said that the resulting organ stress is a direct consequence of the body's struggle to maintain a stable internal temperature [1, 2]. Without adequate cooling, the internal organs are subjected to levels of heat that can cause permanent damage or acute illness [1, 3].

“Extreme heat strains the heart, raises the risk of dehydration and heat‑related illness.”

The intersection of rising global temperatures and high humidity creates a physiological ceiling for human endurance. Because the body relies on sweat evaporation to cool down, high humidity renders this primary defense mechanism ineffective, shifting the burden to the cardiovascular system and potentially leading to multi-organ stress.