The Medi-center, a place to heal your Pokemon where there's a Nurse Joy doing her duty as a Nurse to Pokemon.
Chansey is her assistant and will lead you to where you need to be.
This is also a good place to get information about the place and it's Pokemon.

And if you really need a nap, there are spare beds for Pokemon Trainers to get their beauty sleep.
It does take energy to come up with wicked strategies, comebacks, jumping around, cheering your Pokemon, using muscles you never used before when you're flying your Pokemon or surfing, ect.