The length of time that Great Pyrenees dogs stay in heat is around 2 to 4 weeks.
With my Great Pyrenees dog she stayed in heat for 4 weeks but some may only stay in heat for 2 weeks.
It depends on the dog but the Great Pyrenees dog should be out of the heat cycle after 4 weeks but if not it's still normal.
The dog will come out of heat and you'll know when the dogs heat cycle is over when all of her vulva returns to its normal size and there's no more bleeding or discharge.
When your Great Pyrenees dog or any other dog is in heat you can help calm her by giving her more exercise, paying more attention to her, giving her interactive dog toys etc.
You can also get your dog an anxiety coat that helps calm her down or just wait it out and after 4 weeks or sooner the heat cycle in the dog should be over.