– an early stage of dangerous and deadly Hyperthermia, also known as Heat Prostration or Heat Exhaustion.
Body temperatures above 104°F can be life threatening. The body loses heat through sweating (evaporative cooling), so ambient temperature and humidity factor into to heat stress situations. Using a Wet Bulb Temperature is good, but Wet Bulb Globe Temperature (WBGT) is a better measurement as it takes into account radiant heat from building surfaces (eg. attic roofs and walls) as well as the sun.