There are many reasons for the appearance of weakness, fatigue and dizziness. The causes of the above phenomena can be fatigue, anemia, heart disease, electrolyte disorders, cardiac and physical diseases, etc., as follows: First, fatigue: excessive fatigue and lack of rest can cause the above phenomena. Second, anemia: anemia refers to the low concentration of hemoglobin in the patient’s body. Since hemoglobin is mainly a protein that carries oxygen, if it decreases, the whole body will become ischemic and hypoxic, so weakness and dizziness will occur. Third, heart disease: Heart disease includes congenital heart disease, as well as arrhythmias and coronary heart disease that occur in adulthood, which can also lead to weakness and dizziness. Fourth, electrolyte disorders: electrolyte disorders, especially hypokalemia, can also appear the above phenomenon. Fifth, psychosomatic diseases: some psychosomatic diseases, such as severe anxiety and depression, can also appear dizziness and weakness.