What effect does evaporative cooling have on firefighters in high humidity?

Evaporative cooling plays a crucial role in the body's ability to regulate temperature, especially during physical exertion, such as firefighting. Under normal conditions, sweat evaporating from the skin's surface helps to cool the body down. However, in high humidity, the amount of moisture already present in the air reduces the rate at which sweat can evaporate.

As a result, if the air is saturated with moisture, sweat does not cool the skin effectively, making it more challenging for the body to release heat and maintain its internal temperature. This can lead to overheating, as the body's natural cooling mechanisms become less effective. Consequently, firefighters operating in high humidity may struggle with maintaining their stamina and could be at a higher risk for heat-related illnesses. Thus, the difficulty in regulating internal temperature in humid conditions is a significant factor that impacts the performance and safety of firefighters.