questions! : carrying water

[David planning Le Chemin de St Jacques/El Camino de Santiago]

Here's a question I hadn't thought of before:   since I began long distance
hiking, I've come to prefer gatorade-type drinks above all else - refreshing
even when tepid, no beery complications.
And now you can buy some at practically every gas station in the US at
practically any hour of the day or night.    I am well aware that many
people can't stand gatorade-style drinks!

I don't need real gatorade, but I am wondering if there is something similar
widely available in France and Spain?    What would I ask for, generically
speaking?     Buying premixed (rather than mixing my own from powder) avoids
questions about whether the local fuente is good enough to drink - an issue
for me since I am rather sensitive to digestive upsets.

And I have to put in a good word for coke-like drinks for persons on the
edge of heat exhaustion - the combination of caffeine+sugar+cold+carbonation
seems synergistic somehow.    Real coke is not necessary, any imitation will
do, but it does need real caffeine and real sugar.    Persons who are over
the edge into heat EXHAUSTION
need to follow the usual first aid rules.    Persons who are way
over the edge into heat STROKE need to be treated for a life-threatening
medical emergency.    If you don't know the difference, it might be good
to review, especially if traveling in the height of the summer season.
Especially older persons new to long distance hiking are susceptible to
underestimating these conditions.     Diabetics have their own special
additional considerations as well.