The causes of dizziness in children who stand up include physiological reactions and anemia, as follows: 1. Physiological reactions: If a child squats for too long and suddenly stands up quickly, it can cause dizziness, which is due to a temporary dizziness caused by a significant increase in blood circulation in the lower extremities and a decrease in the amount of blood in the head when standing up, and the dizziness will naturally ease after a few minutes; 2. Anemia: Anemia in children can also cause dizziness when standing up, and the face is often pale, so you can test the hemoglobin in the blood routine, and if the hemoglobin concentration drops significantly, you can confirm that the dizziness is caused by anemia.