Water acts as a radiator in a car. Besides hydrating and carrying nutrients and a host of other things, it cools the body, especially if you sweat a lot like me. If I'm outside in the hot, summer sun for several hours doing yard work, I need to be cooled down, or else risk heat exhaustion. Cool water does that. Even your body says that much. Try doing that and drinking warm water instead of cold and see how you feel. But sometimes cooling is not an issue, such as trying to stay warm in the house at winter time, then we drink warm beverages mostly made of water (such as tea or coffee). In that case, the water helps the body to heat up. Pretty much commonsense to me.
