What causes high blood pressure?

There are two types of hypertension. Each type has a different cause.

Primary hypertension

Primary hypertension is also called essential hypertension. This kind of hypertension develops over time with no identifiable cause. Most people have this type of high blood pressure.

Researchers are still unclear what mechanisms cause blood pressure to slowly increase. A combination of factors may play a role. These factors include:

Genes: Some people are genetically predisposed to hypertension. This may be from gene mutations or genetic abnormalities inherited from your parents.

Physical changes: If something in your body changes, you may begin experiencing issues throughout your body. High blood pressure may be one of those issues. For example, it’s thought that changes in your kidney function due to aging may upset the body’s natural balance of salts and fluid. This change may cause your body’s blood pressure to increase.

Environment: Over time, unhealthy lifestyle choices like lack of physical activity and poor diet can take their toll on your body. Lifestyle choices can lead to weight problems. Being overweight or obese can increase your risk for hypertension.

Secondary hypertension

Secondary hypertension often occurs quickly and can become more severe than primary hypertension. Several conditions that may cause secondary hypertension include:

• kidney disease
• obstructive sleep apnea
• congenital heart defects
• problems with your thyroid
• side effects of medications
• use of illegal drugs
• alcohol abuse or chronic use
• adrenal gland problems
• certain endocrine tumors

Diagnosing high blood pressure

Diagnosing hypertension is as simple as taking a blood pressure reading. Most doctors’ offices check blood pressure as part of a routine visit. If you don’t receive a blood pressure reading at your next appointment, request one.

If your blood pressure is elevated, your doctor may request you have more readings over the course of a few days or weeks. A hypertension diagnosis is rarely given after just one reading. Your doctor needs to see evidence of a sustained problem. That’s because your environment can contribute to increased blood pressure, such as the stress you may feel by being at the doctor’s office. Also, blood pressure levels change throughout the day.

If your blood pressure remains high, your doctor will likely conduct more tests to rule out underlying conditions. These tests can include:

• urine test
• cholesterol screening and other blood tests
• test of your heart’s electrical activity with an electrocardiogram (EKG, sometimes referred to as an ECG)
• ultrasound of your heart or kidneys

These tests can help your doctor identify any secondary issues causing your elevated blood pressure. They can also look at the effects high blood pressure may have had on your organs.

During this time, your doctor may begin treating your hypertension. Early treatment may reduce your risk of lasting damage.

How to understand high blood pressure readings

Two numbers create a blood pressure reading:

• Systolic pressure: This is the first, or top, number. It indicates the pressure in your arteries when your heart beats and pumps out blood.
• Diastolic pressure: This is the second, or bottom, number. It’s the reading of the pressure in your arteries between beats of your heart.

Five categories define blood pressure readings for adults:

• Healthy:A healthy blood pressure reading is less than 120/80 millimeters of mercury (mm Hg).
• Elevated:The systolic number is between 120 and 129 mm Hg, and the diastolic number is less than 80 mm Hg. Doctors usually don’t treat elevated blood pressure with medication. Instead, your doctor may encourage lifestyle changes to help lower your numbers.
• Stage 1 hypertension: The systolic number is between 130 and 139 mm Hg, or the diastolic number is between 80 and 89 mm Hg.
• Stage 2 hypertension: The systolic number is 140 mm Hg or higher, or the diastolic number is 90 mm Hg or higher.
• Hypertensive crisis: The systolic number is over 180 mm Hg, or the diastolic number is over 120 mm Hg. Blood pressure in this range requires urgent medical attention. If any symptoms such as chest pain, headache, shortness of breath, or visual changes occur when blood pressure is this high, medical care in the emergency room is needed.

A blood pressure reading is taken with a pressure cuff. For an accurate reading, it’s important you have a cuff that fits. An ill-fitting cuff may deliver inaccurate readings.

Blood pressure readings are different for children and teenagers. Ask your child’s doctor for the healthy ranges for your child if you’re asked to monitor their blood pressure.