How will the red blood cells change during the trip to Tibet?

The reason upstairs is wrong, not because the human body needs more oxygen, but because the oxygen in the plateau is thin, and the human body can't get enough oxygen, so the body is stimulated and the number of red blood cells is increased. The reason is the same as iodine deficiency in human body, which leads to compensatory hyperplasia of thyroid gland and big neck disease. The difference is that the average person's red blood cells will return to normal when there is enough oxygen.