Healthy arteries are flexible, strong and elastic. Their inner lining is smooth so that blood flows freely, supplying vital organs and tissues with nutrients and oxygen.

Over time, high blood pressure increases the pressure of blood flowing through the arteries. This may cause:

• Damaged and narrowed arteries. High blood pressure can damage the cells of the arteries' inner lining. When fats from food enter the bloodstream, they can collect in the damaged arteries. In time, the artery walls become less elastic. This limits blood flow throughout the body.
• Aneurysm. Over time, the constant pressure of blood moving through a weakened artery can cause part of the artery wall to bulge. This is called an aneurysm. An aneurysm can burst open and cause life-threatening bleeding inside the body. Aneurysms can form in any artery. But they're most common in the body's largest artery, called the aorta.

High blood pressure can cause many heart conditions, including:

• Coronary artery disease. High blood pressure can narrow and damage the arteries that supply blood to the heart. This damage is known as coronary artery disease. Too little blood flow to the heart can lead to chest pain, called angina. It can lead to irregular heart rhythms, called arrhythmias. Or it can lead to a heart attack.
• Heart failure. High blood pressure strains the heart. Over time, this can cause the heart muscle to weaken or become stiff and not work as well as it should. The overwhelmed heart slowly starts to fail.
• Enlarged left heart. High blood pressure forces the heart to work harder to pump blood to the rest of the body. This causes the lower left heart chamber, called the left ventricle, to thicken and to enlarge. A thickened and enlarged left ventricle raises the risk of heart attack and heart failure. It also increases the risk of death when the heart suddenly stops beating, called sudden cardiac death.
• Metabolic syndrome. High blood pressure raises the risk of metabolic syndrome. This syndrome is a cluster of health conditions that can lead to can lead to heart disease, stroke and diabetes. The health conditions that make up metabolic syndrome are high blood pressure, high blood sugar, high levels of blood fats called triglycerides, low levels of HDL cholesterol, which is the "good" cholesterol, and too much body fat around the waist.

The brain depends on a nourishing blood supply to work right. High blood pressure may affect the brain in the following ways:

• Transient ischemic attack (TIA). Sometimes this is called a ministroke. A TIA happens when the blood supply to part of the brain is blocked for a short time. Hardened arteries or blood clots caused by high blood pressure can cause TIAs. A TIA is often a warning sign of a full-blown stroke.
• Stroke. A stroke happens when part of the brain doesn't get enough oxygen and nutrients. Or it can happen when there is bleeding inside or around the brain. These problems cause brain cells to die. Blood vessels damaged by high blood pressure can narrow, break or leak. High blood pressure also can cause blood clots to form in the arteries leading to the brain. The clots can block blood flow, raising the risk of a stroke.
• Dementia. Narrowed or blocked arteries can limit blood flow to the brain. This could lead to a certain type of dementia, called vascular dementia. A single stroke or multiple tiny strokes that interrupt blood flow to the brain also can cause vascular dementia.
• Mild cognitive impairment. This condition involves having slightly more troubles with memory, language or thinking than other adults your age have. But the changes aren't major enough to impact your daily life, as with dementia. High blood pressure may lead to mild cognitive impairment.

Kidneys filter extra fluid and waste from the blood — a process that requires healthy blood vessels. High blood pressure can damage the blood vessels in and leading to the kidneys. Having diabetes along with high blood pressure can worsen the damage.

Damaged blood vessels prevent the kidneys from being effective at filtering waste from the blood. This allows dangerous levels of fluid and waste to collect. When the kidneys don't work well enough on their own, it's a serious condition called kidney failure. Treatment may include dialysis or a kidney transplant. High blood pressure is one of the most common causes of kidney failure.

High blood pressure can damage the tiny, delicate blood vessels that supply blood to the eyes, causing:

• Damage to the blood vessels in the retina, also called retinopathy. The retina is a layer of light-sensing cells at the back of the eye. Damage to the blood vessels in the retina can lead to bleeding in the eye, blurred vision and complete loss of vision. Having diabetes along with high blood pressure raises the risk of retinopathy.
• Fluid buildup under the retina, also called choroidopathy. This condition can result in distorted vision or sometimes scarring that makes vision worse.
• Nerve damage, also called optic neuropathy. Blocked blood flow can damage the nerve that sends light signals to the brain, called the optic nerve. The damage can lead to bleeding within the eye or vision loss.

Trouble getting and keeping an erection is called erectile dysfunction. It becomes more and more common after age 50. But people with high blood pressure are even more likely to have erectile dysfunction. That's because limited blood flow caused by high blood pressure can block blood from flowing to the penis.

High blood pressure can reduce blood flow to the vagina. Reduced blood flow to the vagina can lead to less sexual desire or arousal, vaginal dryness, or trouble having orgasms.

High blood pressure usually is an ongoing condition that slowly causes damage over years. But sometimes blood pressure rises so quickly and seriously that it becomes a medical emergency. When this happens, treatment is needed right away, often with hospital care.

In these situations, high blood pressure can cause:

• Blindness.
• Chest pain.
• Complications in pregnancy, such as the blood pressure-related conditions preeclampsia or eclampsia.
• Heart attack.
• Memory loss, personality changes, trouble concentrating, irritable mood or gradual loss of consciousness.
• Serious damage to the body's main artery, also called aortic dissection.
• Stroke.
• Sudden impaired pumping of the heart, leading to fluid backup in the lungs that results in shortness of breath, also called pulmonary edema.
• Sudden loss of kidney function.