Cold Water vs Warm Water.
Cold Water:
Body has to expend energy to warm up water in order to use it.
Helps to cool down the body after workout / exercise.
Constricts blood vessels, this reduces hydration & absorption ability.
Solidify fats from food, causing body to work harder to digest.

Warm Water:
Soothes blood vessels, allows better hydration.
Helps move the fats along, reducing risks of clogged arteries, & allows better digestion.
Helps to flush the kidneys & improve bowel movements.
When having fever, warm water reduces the body's effort to fight the virus.