High renin activity in young people may be caused by secondary hypertension, paraglomerular cell tumor, renal ischemia and so on. 1. Secondary hypertension: elevated renin can be seen in secondary hypertension, such as renal artery stenosis, renal hypertension caused by various reasons, etc. Some primary hypertension can also have elevated renin activity. 2. Tumor of paraglomerular cells: Tumor of paraglomerular cells can also secrete renin independently, leading to elevated renin activity. 3. Renal ischemia: renin is a kind of protein hydrolase synthesized and secreted by glomerular paraglomerular cells, and after a series of changes, it is transformed into angiotensin Ⅱ, which has the effect of elevating the blood pressure, and when the renal blood flow is reduced, renin can be increased. If patients find that renin activity is elevated, it is recommended that they go to a regular hospital in time, improve the examination to clarify the cause of the disease, and then standardize the treatment under the guidance of the doctor.