There are primary causes of high blood pressure, which may be related to environmental and genetic factors, or may be caused by organic diseases, which are secondary hypertension. 1. Primary hypertension: It is the main type of hypertension. The specific cause of primary hypertension is still unclear, and it may be caused by a variety of factors that lead to the elevation of blood pressure level. Environmental factors, such as stressful life and mental tension, can cause sympathetic nerve excitation and raise blood pressure levels. Genetic factors may also be a cause of hypertension. 2. Secondary hypertension: It is mostly seen in renal diseases, such as renal artery stenosis, which can lead to increased secretion of renin, causing the expansion of arterial vasculature throughout the body to raise the blood pressure. Adrenal diseases such as pheochromocytoma can over-secrete catecholamines, leading to elevated blood pressure levels. There are many reasons for high blood pressure, and if you find that your blood pressure is elevated, you need to consult a doctor in time to find out the cause and give active treatment according to the doctor’s instructions, so as to avoid any delay in your condition.