High blood pressure
High blood pressure is a common condition in which the force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease. Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke. High blood pressure typically develops over many years, and it affects nearly everyone eventually. Fortunately, high blood pressure can be easily detected.
For an In-depth look in High Blood Pressure/Hypertension: http://www.mayoclinic.com/health/high-blood-pressure/DS00100/TAB=indepth