If you have a headache when you lie down and sit up, it is important to monitor your blood pressure. For most patients, blood pressure will be high in the lying position, and when the lying position changes to the sitting or standing position, the blood in the body will be redistributed, and some of the venous blood will stagnate in the sagging parts of the body, which will cause the amount of blood returning to the heart to decrease, and the arterial blood pressure will drop, and the drop will not exceed 20 mmHg. There is a clear correlation between the level of blood pressure. Headaches appear when blood pressure rises and can be reduced or disappear when blood pressure falls. Headaches caused by other causes, such as headaches caused by mental tension and anxiety, and neuropathic headaches, are not significantly related to the level of blood pressure. Headaches related to postural changes are considered to be caused by hypertension.