The most common symptom of moderate anemia is weakness, and the corresponding manifestations of each system are as follows: 1. Nervous system: it can manifest as headache, dizziness, insomnia, dreaminess, tinnitus, blurred vision, memory loss, and lack of concentration; 2. Respiratory system: it can manifest as deepening and speeding up of breathing; 3. Circulatory system: it can manifest as panic, shortness of breath after activity, and even heart failure; 4. Digestive system: it can manifest as Indigestion, abdominal distension, loss of appetite, change in stool pattern and character. If anemia is not corrected for a long time, the function of the above systems will gradually deteriorate, which may lead to organ failure. Anemia is not an independent clinical disease, and many diseases can have anemia manifestations.