Originally Posted by cyccommute
Another advantage of Camelbaks is that they are well insulated. Pack a bag of ice in them (you can get most of a 7 lb bag of ice in one), fill with water and you'll have cold water for most of the day...even in over 100 F temperatures. Water bottles can't even come close to that. They last less than an hour even at 90 F.
Please be careful doing this. drinking ice cold water in over 100F, really shocks your system. I have a uncle who almost died doing this