The human body can tolerate a maximum internal temperature of around \(108.4^{\circ }F\) (\(42^{\circ }C\)), at which point proteins begin to denature and damage is irreparable. Externally, the tolerance limit is more complex and depends on factors like humidity, but a recent study suggests the limit is much lower than previously thought, around a wet-bulb temperature of \(30.6^{\circ }C\) (\(87^{\circ }F\)) under mild exertion.
Maximum internal temperature The body's internal temperature can only reach about \(108.4^{\circ }F\) (\(42^{\circ }C\)) before proteins are irreversibly damaged, leading to severe consequences like brain damage and likely death.A body temperature of \(109.4^{\circ }F\) (\(43^{\circ }C\)) or higher is considered the upper limit for survival, and survival is unlikely above this point.
Environmental tolerance Wet-bulb temperature: This is a key measurement because it accounts for both temperature and humidity, representing how effectively the body can cool itself through sweating.Theoretical limit: A widely cited theoretical limit is a wet-bulb temperature of \(95^{\circ }F\) (\(35^{\circ }C\)), which corresponds to high temperatures and high humidity.Real-world limit: A recent study found that the actual limit for young, healthy adults is much lower, around \(30.6^{\circ }C\) (\(87^{\circ }F\)) wet-bulb temperature under mild exertion.Dry heat: In very dry conditions with wind, humans can tolerate higher dry-bulb temperatures for longer, as sweat evaporates more quickly.
