A study found that sports drinks work because
they activate the pleasure center of your brain. You don't even have
to drink them, just swishing some around in your mouth and spitting
it out has the same effect.
The carbohydrates in the drink stimulate receptors in your mouth
that then send your brain messages that things are all great. Your
brain then becomes more active in the pleasure center, allowing you
to enjoy feeling the burn longer than someone without a sugary
drink.