I remember as a 10-12 year old playing little league baseball in 90-100 degree heat and after the game our coaches gave all us kids (winning and losing team) an ice cold can of Coke. Wow, we sure needed some liquid but I would never go for that beverage (or any soda) now nor recommend it to cool off. Ice water - just about perfect!
I selected iced tea, however my first choice would be an Arnold Palmer (1/2 iced tea, 1/2 lemonade). But iced tea is close enough for this one, as a sweet tea (or unsweetened tea) is also near the top.