High blood pressure (hypertension) is a common condition in which the long-term 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 both 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. A blood pressure reading is given in millimeters of mercury (mm Hg). It has two numbers.
- Top number (systolic pressure): The first, or upper, number measures the pressure in your arteries when your heart beats.
- Bottom number (diastolic pressure): The second, or lower, number measures the pressure in your arteries between beats.
High blood pressure can lead to complications including:
- Heart attack or stroke: High blood pressure can cause hardening and thickening of the arteries (atherosclerosis), which can lead to a heart attack, stroke or other complications.
- Aneurysm: Increased blood pressure can cause your blood vessels to weaken and bulge, forming an aneurysm. If an aneurysm ruptures, it can be life-threatening.
- Heart failure: To pump blood against the higher pressure in your vessels, the heart has to work harder. This causes the walls of the heart’s pumping chamber to thicken (left ventricular hypertrophy). Eventually, the thickened muscle may have a hard time pumping enough blood to meet your body’s needs, which can lead to heart failure.
- Weakened and narrowed blood vessels in your kidneys: This can prevent these organs from functioning normally.
- Thickened, narrowed or torn blood vessels in the eyes: This can result in vision loss.
- Metabolic syndrome: This syndrome is a group of disorders of your body’s metabolism, including increased waist size, high triglycerides, decreased high-density lipoprotein (HDL) cholesterol (the “good” cholesterol), high blood pressure and high insulin levels. These conditions make you more likely to develop diabetes, heart disease and stroke.
- Trouble with memory or understanding: Uncontrolled high blood pressure may also affect your ability to think, remember and learn. Trouble with memory or understanding concepts is more common in people with high blood pressure.
- Dementia: Narrowed or blocked arteries can limit blood flow to the brain, leading to a certain type of dementia (vascular dementia). A stroke that interrupts blood flow to the brain also can cause vascular dementia.