Low blood pressure can cause drowsiness and dizziness. Low blood pressure usually causes insufficient arterial blood oxygen saturation and therefore low partial pressure of oxygen and high partial pressure of carbon dioxide, which can lead to a decrease in oxygenation capacity, and then drowsiness can occur frequently. When the arterial systolic and diastolic blood pressure is too low, the clinical symptoms and manifestations of dizziness and headache will be caused by insufficient blood supply to the cerebral blood vessels or ischemia, stenosis, or spasm of the blood vessels, and the symptoms of drowsiness, or dizziness and headache due to low blood pressure can be improved by timely adjustment and correction of blood pressure, but it is important to find out whether the above-mentioned conditions are caused by low blood pressure.