Most people with high blood pressure have no signs or symptoms, even if blood pressure readings reach dangerously high levels.
Although a few people with early-stage high blood pressure may have dull headaches, dizzy spells or a few more nosebleeds than normal, these signs and symptoms usually don't occur until high blood pressure has reached a severe or life-threatening stage.
When to see a doctor
You'll likely have your blood pressure taken as part of a routine doctor's appointment.
Ask your doctor for a blood pressure reading at least every two years starting at age 18. Blood pressure should be checked in both arms to determine if there is a difference. Your doctor will likely recommend more frequent readings if you've already been diagnosed with high blood pressure or other risk factors for cardiovascular disease. Children age 3 and older will usually have their blood pressure measured as a part of their yearly checkups.
If you don't regularly see your doctor, you may be able to get a free blood pressure screening at a health resource fair or other locations in your community. You can also find machines in some stores that will measure your blood pressure for free, but these machines can give you inaccurate results.
There are two types of high blood pressure.
Primary (essential) hypertension
For most adults, there's no identifiable cause of high blood pressure. This type of high blood pressure, called essential hypertension or primary hypertension, tends to develop gradually over many years.
Some people have high blood pressure caused by an underlying condition. This type of high blood pressure, called secondary hypertension, tends to appear suddenly and cause higher blood pressure than does primary hypertension. Various conditions and medications can lead to secondary hypertension, including:
- Kidney problems
- Adrenal gland tumors
- Thyroid problems
- Certain defects in blood vessels you're born with (congenital)
- Certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs
- Illegal drugs, such as cocaine and amphetamines
- Alcohol abuse or chronic alcohol use
- Obstructive sleep apnea
High blood pressure has many risk factors, including:
- Age. The risk of high blood pressure increases as you age. Through early middle age, or about age 45, high blood pressure is more common in men. Women are more likely to develop high blood pressure after age 65.
- Race. High blood pressure is particularly common among blacks, often developing at an earlier age than it does in whites. Serious complications, such as stroke, heart attack, and kidney failure, also are more common in blacks.
- Family history. High blood pressure tends to run in families.
- Being overweight or obese. The more you weigh the more blood you need to supply oxygen and nutrients to your tissues. As the volume of blood circulated through your blood vessels increases, so does the pressure on your artery walls.
- Not being physically active. People who are inactive tend to have higher heart rates. The higher your heart rate, the harder your heart must work with each contraction and the stronger the force on your arteries. Lack of physical activity also increases the risk of being overweight.
- Using tobacco. Not only does smoking or chewing tobacco immediately raise your blood pressure temporarily, but the chemicals in tobacco can damage the lining of your artery walls. This can cause your arteries to narrow, increasing your blood pressure. Secondhand smoke also can increase your blood pressure.
- Too much salt (sodium) in your diet. Too much sodium in your diet can cause your body to retain fluid, which increases blood pressure.
- Too little potassium in your diet. Potassium helps balance the amount of sodium in your cells. If you don't get enough potassium in your diet or retain enough potassium, you may accumulate too much sodium in your blood.
- Too little vitamin D in your diet. It's uncertain if having too little vitamin D in your diet can lead to high blood pressure. Vitamin D may affect an enzyme produced by your kidneys that affects your blood pressure.
Drinking too much alcohol. Over time, heavy drinking can damage your heart. Having more than two drinks a day for men and more than one drink a day for women may affect your blood pressure.
If you drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.
- Stress. High levels of stress can lead to a temporary increase in blood pressure. If you try to relax by eating more, using tobacco or drinking alcohol, you may only increase problems with high blood pressure.
- Certain chronic conditions. Certain chronic conditions also may increase your risk of high blood pressure, such as kidney disease and sleep apnea.
Sometimes pregnancy contributes to high blood pressure, as well.
Although high blood pressure is most common in adults, children may be at risk, too. For some children, high blood pressure is caused by problems with the kidneys or heart. But for a growing number of kids, poor lifestyle habits, such as an unhealthy diet, obesity and lack of exercise, contribute to high blood pressure.
The excessive pressure on your artery walls caused by high blood pressure can damage your blood vessels, as well as organs in your body. The higher your blood pressure and the longer it goes uncontrolled, the greater the damage.
Uncontrolled high blood pressure can lead to:
- 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, your heart muscle thickens. 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 cluster of disorders of your body's metabolism, including increased waist circumference; high triglycerides; low high-density lipoprotein (HDL); or "good," cholesterol; high blood pressure; and high insulin levels.
If you have high blood pressure, you're more likely to have other components of metabolic syndrome. The more components you have, the greater your risk of developing diabetes, heart disease or 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.