If you're ever stuck out in the wilderness, remember what survival experts call 'the Rule of Threes'.
You can live 3 minutes without air, though we don't recommend trying. In a harsh environment — it's snowing, say — you have 3 hours to survive without shelter. After 3 days, you need water or you'll perish. You can make it 3 weeks without food, though we promise you that won't be fun.
Despite this possibly helpful rule, some people have survived 8 to 10 days without water. Again, leave such shenanigans to the truly desperate.
As 65 percent of the human body, water is essential to people.
Water flows through the blood, carrying oxygen and nutrients to cells and flushing wastes out of our bodies. It cushions our joints and soft tissues. Without water as a routine part of our intake, we cannot digest or absorb food.