Great Pyrenees dogs do need some exercise but not as much exercise as smaller dogs.
The Great Pyrenees dog is a large breed of dog that needs a lot of space both indoor space and outdoor space and it's better to have enough space outdoors to allow the Great Pyrenees dog to exercise freely to it's hearts desire.
If you live in an apartment the Great Pyrenees is not suitable for apartment life so if you live in an apartment then you'll have to get another dog instead of a Great Pyrenees.