Any question answered...

milk is better than water for hydration too

There was a TV experiment where two groups of people did similar exercises and then rehydrated with similar quantities of either water or milk, and they compared the water loss (through urine measurement).

The group that drank milk lost less fluid afterwards, which would indicate that drinking milk means more fluid is retained, however it isn't that simple.

1) Milk contains calories, and so some fluid will be required to store the glycogen that is created from ingesting calories. So drinking milk might actually mean you're less hydrated than drinking plain water, despite weeing out less fluid subsequently.
2) It doesn't scale. If you need to drink 2l of water to fix your dehydration you're not going to stomach drinking 2l of milk.
3) Water is cheap and abundant.

A pint of milk (or similar) after exercise is good, but subsequent rehydration should be water or electrolyte drink.