The main reasons for unstable blood pressure are related to inaccurate measurement, emotional changes, physical diseases or irregular medication. 1. Inaccurate measurement: If the measurement of blood pressure is not standardized, it will easily affect the measurement of blood pressure, thus forming the phenomenon of unstable blood pressure. 2. Emotional changes: emotional instability, such as nervousness, anxiety or excitement, can easily cause fluctuations in blood pressure, resulting in unstable high and low blood pressure. 3. Physical diseases: If there are physical diseases, such as lung infections, or malnutrition and gastrointestinal bleeding, etc., it can also cause blood pressure fluctuations, resulting in unstable blood pressure symptoms. 4. Irregular medication: For patients with high blood pressure, if the medication is not regular, it is easy to cause unstable blood pressure, thus producing high and low symptoms. Usually pay attention to monitoring and controlling blood pressure, maintain stable emotion and regular life habits, and take medication regularly, so as to avoid unstable blood pressure induced cardiovascular and cerebrovascular diseases. If your blood pressure is unstable for a long time, it is recommended that you go to the hospital in time and have a reasonable diagnosis and treatment under the guidance of a professional doctor.