The causes of unstable blood pressure in the elderly mainly include irregular medication, body position, emotion, lack of sleep, and vascular calcification. 1. Body position: the elderly are prone to hypotension caused by change of body position, for example, if the elderly get up suddenly after sitting for a long time, it will induce postural hypotension. 2. Emotions: If the elderly are easily agitated or have large emotional ups and downs in a short period of time, it will also cause fluctuations in blood pressure, leading to unstable blood pressure. 3. Irregular medication: the elderly have irregular medication phenomenon, often eat a meal and miss a meal, consciously good blood pressure will stop taking medication on their own, which will cause unstable blood pressure in the elderly. 4. Lack of sleep: poor sleep quality, night dreams, easy to wake up, etc., leading to endocrine disorders, abnormal contraction of blood vessels, which can cause blood pressure instability. 5. Vascular calcification: most of the elderly people have vascular calcification, and the elasticity of blood vessels is weakened, and the blood pressure will become unstable. 6. Others: Renin is secreted by glomerular paraglomerular cells of the kidneys and is mainly involved in the formation of the renin-angiotensin system, which participates in the regulation of blood pressure in the body. If the secretion of renin level of the elderly is not balanced, it will lead to unstable blood pressure. Elderly people with unstable blood pressure are prone to dizziness, falls, acute hypertension, hypertensive cerebral hemorrhage and other malignant events. Recent fluctuations in blood pressure are recommended for hospital consultation.