The higher your blood pressure and the longer it remains uncontrolled, the greater is the damage. Uncontrolled high blood pressure can cause many diseases and problems such as heart attack, stroke, kidney problems, etc. High blood pressure can cause hardening and thickening of the arteries (a condition called atherosclerosis), which can cause severe complications.
Mostly, high blood pressure (also called hypertension) shows no symptoms at all in the beginning. This means that people with high blood pressure can get damage to their heart, kidneys, eyes, and circulation without feeling it at all. Symptoms appear after it has caused some damage already.