High blood pressure is nicknamed “the silent killer” because it usually causes no symptoms (though, on occasion, hypertensive individuals may experience headaches).

High blood pressure is nicknamed "the silent killer" because it usually causes no symptoms (though, on occasion, hypertensive individuals may experience headaches). Many people have the problem for years without knowing it. Yet just because high blood pressure is symptomless doesn't mean it is harmless. In fact, it may be doing serious damage inside your body while it goes undetected.

Common High Blood Pressure Symptoms

High blood pressure is generally a chronic condition. While secondary hypertension may cause blood pressure to spike quickly, primary hypertension is caused by factors that develop over time, like coronary artery disease and obesity. Typically, the only way to know you have it is to get your blood pressure tested.

Learn the symptoms of pulmonary arterial hypertension »

Rare High Blood Pressure Symptoms

Rarely, people with chronic high blood pressure might have symptoms such as:

  • Dull headaches
  • Dizzy spells
  • Nosebleeds

Read about other causes of dizziness or nosebleeds.

Emergency High Blood Pressure Symptoms

If any symptoms occur, it is usually only when blood pressure spikes suddenly and extremely enough to be considered a medical emergency. This is called a hypertensive crisis.

Hypertensive crisis is defined as a blood pressure reading of 180 or above for the systolic pressure (first number) or 110 or above for the diastolic pressure (second number). If you are checking your own blood pressure and get a reading that high, wait a few minutes and then check again to make sure the first reading was accurate. Other symptoms of a hypertensive crisis may include:

  • Severe headache
  • Severe anxiety
  • Shortness of breath
  • Nosebleed

If, after waiting a few minutes, your second blood pressure reading is still 180 or above, or if you have other symptoms of a hypertensive crisis, don't wait to see whether your blood pressure comes down on its own. Call 911 immediately. If that isn't an option, have someone drive you to the emergency room.

Emergency hypertensive crisis can result in severe complications, including fluid in the lungs, brain swelling or bleeding, a tear in the heart's main artery, stroke, or seizures for pregnant women with eclampsia..