|Dehydration plays a major factor in death. A body loses about a liter of water each hour while hiking. That number is more than doubled in hot weather. The human body cannot absorb water nearly that quickly, so it’s nearly impossible to replace it even if a hiker is carrying enough.|
In other words, each hour, the body can lose 2 liters of water but only replace .5 liters, leaving the body at a 1.5-liter deficit of water each hour.