They drink equal amounts of dehydrating beverages. That includes any drink with caffeine or alcohol in it. In effect these cancel out the benefits of water. Every system in your body, from your brain to your bowel depends on water. Water regulates body temperature, transports nutrients and oxygen, carries away waste, helps de-toxify the kidney's and liver and cushions the body from injury.
Water is the body's air conditioning system.
When you become to warm, the loss of water through the pores of the skin, sweat glands and lungs prevents the body from building up to much internal heat. Everyday you lose ten to twelve cups of water that needs to be replaced to maintain your body's fluid balance. Dr. Karen Johnson Don't rely on thirst to tell you when to drink. By the time thirst hits, you are already mildly dehydrated. For you sports enthusiasts who are out in the heat sports drinks are good.