Will Fujian people lack oxygen when they go to Xinjiang?

This is not necessarily true. If your place is at the same altitude as Xinjiang, there will be no lack of oxygen. If your place is at a low altitude, but the place you are going to is at a high altitude with a large height difference, you may be deprived of oxygen, which is also related to your personal state. People who exercise regularly will have stronger tolerance to hypoxia.