If blood pressure becomes dangerously high, it may cause a headache and other symptoms. However, more research into the link between high blood pressure and headaches is necessary.

When symptoms of high blood pressure do occur, they may include a severe headache. People who suspect that they have symptoms of high blood pressure should not ignore them.

This article explains when high blood pressure might cause a headache, what additional symptoms a person might experience, and when to seek immediate medical treatment.

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Study results provide conflicting evidence on whether high blood pressure causes headaches.

Evidence supporting the idea

According to a paper in the Iranian Journal of Neurology, headaches due to high blood pressure typically occur on both sides of the head. The headache pain tends to pulsate and often gets worse with physical activity.

According to the authors, high blood pressure can cause headaches because it affects the blood-brain barrier.

In very severe cases, when blood pressure is extremely high, hypertension can result in excess pressure on the brain, which can cause blood to leak from the blood vessels in this organ.

This leakage causes edema, or swelling, which is problematic because the brain sits within the skull and has no space to expand.

The swelling places further pressure on the brain and causes symptoms that include a headache, dizziness, nausea, confusion, weakness, seizures, and blurred vision. If a person receives treatment to lower their blood pressure, their symptoms will usually improve within an hour.

Evidence contradicting the idea

The American Heart Association (AHA) maintains that people do not usually experience headaches when their blood pressure is high unless it goes above a reading of 180/120 millimeters of mercury (mm Hg). At this point, it becomes a hypertensive crisis, which is a medical emergency.

Researchers have also looked at whether having regular headaches might affect a person’s overall heart health.

A study in the American Journal of Hypertension followed 1,914 people with hypertension for 30 years and monitored their headaches. The results showed no link between the regular occurrence of headaches and the likelihood of cardiovascular mortality.

Therefore, there is no indication that people with hypertension who have regular headaches will have heart problems. However, the researchers propose that headaches might signal a need for treatment and make people more likely to take antihypertensive medications where necessary.

Many people with high blood pressure experience no symptoms. As a result, high blood pressure is known as a “silent killer.”

When blood pressure increases rapidly and severely, typically up to readings of 180/120 mm Hg or higher, this is known as a hypertensive crisis.

If a person has dangerously high blood pressure but no other symptoms, the condition is called hypertensive urgency. If they are experiencing additional symptoms, it is a hypertensive emergency.

Other symptoms can include:

  • back pain
  • difficulty speaking
  • facial flushing
  • nosebleeds
  • numbness or weakness
  • severe anxiety
  • shortness of breath
  • vision changes

If people have headaches and high blood pressure, they should seek immediate medical attention, as this combination of symptoms could indicate a hypertensive crisis. Without treatment, there is a risk of further organ damage or unwanted side effects.

Doctors classify hypertensive headaches with other related symptoms as a hypertensive emergency. This condition often requires blood pressure control with IV medications.

Examples of these medications include:

  • nicardipine
  • labetalol
  • sodium nitroprusside

It is essential that people do not try to lower their blood pressure at home, even if they have the medications. Reducing blood pressure too quickly can affect the blood flow to the brain, causing unwanted side effects.

Instead, they should go to an emergency room where doctors can help them lower their blood pressure in a safe, controlled environment.

Without treatment, a hypertensive crisis can cause severe complications.

Examples of these include:

Therefore, it is vital that a person does not ignore a severe headache and any other symptoms relating to high blood pressure.

A person should call 911 for emergency medical treatment if they have these symptoms. They should not wait in the hope that their blood pressure will become lower on its own.

According to a 2017 review article, the mortality rate for people going to a coronary care unit with a hypertensive emergency is 4.6%.

Prompt treatment for headaches relating to high blood pressure is vital to reduce a person’s symptoms and minimize the risk of side effects.