Headaches are an extremely common condition with many potential causes — it might be a lack of sleep, too much caffeine, a symptom of high blood pressure (or low blood pressure), or plain old stress. With all these possibilities, it can be hard to pin down what’s causing a headache. 

While high blood pressure is unlikely to be the cause for most people, extremely high blood pressure can potentially lead to a severe headache. 

This guide from HealthTap breaks down what it means to have high blood pressure, how it can affect headaches, and what can be done to treat it. 

What causes high blood pressure?

The heart pumps blood into blood vessels, which carry blood (along with oxygen and other important nutrients) throughout the body.

Blood pressure measures how hard the blood pushes against blood vessels. If blood pressure is high, the heart has to work harder to pump blood. This strain can harden the arteries (a type of blood vessel) and increase the chance of stroke, heart disease, heart attack, or even kidney disease.

A blood pressure reading measures systolic blood pressure (how much pressure is exerted when the heart pumps out blood) and diastolic blood pressure (how much pressure is exerted when the heart relaxes and fills with blood).

In a blood pressure reading, the systolic number goes on top, while the diastolic number goes on the bottom. An example would be 120/80, which is read by the top number first, i.e. “120 over 80.” Blood pressure  is measured in millimeters of mercury (mm Hg), which is a unit of pressure. 

This reading helps healthcare providers understand the health of the cardiovascular system. Too often, high blood pressure is a silent killer that doesn’t show obvious signs that something is wrong, which is why it’s important to get blood pressure checked regularly. 

These are the general ranges for a blood pressure reading: 

• Normal blood pressure: Less than 120/80.

• Elevated blood pressure: 120–129 over 80.

• Stage 1 hypertension: 130–139 over 80–89.

• Stage 2 hypertension: 140+/90+.

• Hypertensive crisis:180+/120+.

Hypertension can often be managed at home with a doctor’s advice. However, a hypertensive crisis is a medical emergency that should be treated immediately.

What causes high blood pressure?

For most people with hypertension, the underlying cause is unknown. This is referred to as “essential hypertension.” 

While the causes of high blood pressure vary between individuals, medical research links hypertension to lifestyle risk factors like diet, exercise, and stress levels. 

While sodium is an essential mineral, some people with hypertension may be sensitive to it. If they eat more salt than they need, their bodies may hold on to extra fluids to get rid of the sodium, which in turn may cause blood pressure to rise. 

Balancing sodium levels isn’t only about eating the right amount of it. It’s also important to eat the right amounts of potassium, calcium, and magnesium, which are all essential minerals that can help balance out sodium in the bloodstream. 

Other risk factors for essential hypertension can include genetics, age, race, exercise level, smoking status, alcohol consumption, and weight. 

While hypertension can occur seemingly on its own, there are also cases where there is an underlying cause behind high blood pressure. This is called “secondary hypertension.” Once the underlying cause has been addressed, a person’s blood pressure generally begins to lower.

Secondary hypertension can result from health issues such as kidney disease, problems with the adrenal glands (which may release hormones that raise blood pressure), birth control pills, and medications that constrict blood vessels (such as those that treat migraines). 

What causes headaches? 

There are two types of headaches: primary and secondary. 

A secondary headache is due to an underlying medical condition, such as a viral infection, head trauma, hypothyroidism, stroke, or brain tumor. Once the underlying cause is addressed, the headache usually goes away.

A primary headache does not have an underlying cause. Instead, it occurs on its own, and usually has to do with irregularities in the pain-sensitive structures of the head, and to some degree, the neck. This can include certain brain regions, surrounding blood vessels, and surrounding nerves.

There are several types of primary headaches. The most common are migraines, cluster headaches, and tension headaches. These usually have triggers that set off an attack, such as emotional stress, lack of sleep, or caffeine withdrawal.  

Can high blood pressure cause headaches?

The research is split on whether or not high blood pressure can, by itself, cause headaches. 

One theory is that extremely high blood pressure can put excess pressure on the brain. This pressure can cause the blood vessels in the brain to expand, leading to brain swelling. Because of the skull’s structure, the brain has nowhere to go, and may begin to press up against the skull, which can lead to pain. 

Some research supports the connection between high blood pressure and headache. For instance, one study found high blood pressure to be the cause of headaches in a group of men with stage 2 hypertension. The study’s participants experienced pain on both sides of the head that worsened with physical activity.  

However, stage 1 and stage 2 hypertension are not well-known causes of headaches from a larger standpoint. For instance, one study followed about 2,000 people with hypertension over the course of 30 years, and there didn’t appear to be a concrete link between high blood pressure and headaches. 

The only exception is a hypertensive crisis. When blood pressure exceeds 180/120, it’s considered a hypertensive crisis, and it can cause a headache. It is often also accompanied by other symptoms, which are important to recognize so emergency care can be sought accordingly. 

What are the symptoms of a hypertensive crisis?

Because it’s a medical emergency, it’s important to be able to recognize the symptoms of a hypertensive crisis. A hypertensive crisis can lead to fluid build-up in the lungs, stroke, kidney failure, heart failure, and other serious health complications.

The best way to check for a hypertensive crisis is with a blood pressure reading. General guidelines suggest it’s best to check blood pressure twice, spaced five minutes apart. If it reads 180/120 or higher both times, a hypertensive crisis is likely. 

A hypertensive crisis can also be accompanied by other symptoms, such as: 

• Blurred vision.

• Mental confusion.

• Shortness of breath.

• Chest pain.

• Dizziness.

• Nausea and vomiting.

• Severe anxiety.

• Unresponsiveness.

• Severe headache.

It’s important for anyone experiencing the above symptoms to go to the emergency room immediately. If not treated in time, a hypertensive emergency can lead to severe complications, some of which may be life-threatening. 

Symptoms can be different in everyone. Even if symptoms don’t seem severe, it’s still important to seek immediate medical care if a blood pressure reading indicates severe hypertension. 

How is a hypertensive crisis treated?  

A hypertensive crisis usually requires blood pressure control with medications. 

Some of the medications used to lower blood pressure in a hypertensive crisis include nicardipine, labetalol, and sodium nitroprusside. These medications work by relaxing the blood vessels, which means that the heart doesn’t have to pump blood as hard. 

Even though blood pressure medications used to manage stage 1 or 2 hypertension may be available at home, they are rarely effective to manage a hypertensive crisis. Emergency medical care is almost always necessary to effectively and safely lower blood pressure in a hypertensive crisis — providers will usually administer medication through an IV for immediate effects, then will monitor high risk patients closely for complications. 

How is high blood pressure treated?

A hypertensive crisis is treated in the emergency room. However, stage 1 and stage 2 hypertension is often managed at home with a combination of medications and lifestyle changes, depending on the primary care provider’s recommended plan of care.

Lifestyle changes

A healthy lifestyle has zero side effects and may be extremely effective for lowering blood pressure. A doctor may recommend the following lifestyle changes: 

• Losing weight
  Being overweight can increase the risk of hypertension. Losing weight by decreasing calorie intake and increasing exercise may help lower blood pressure. 

• Quitting smoking
  The chemicals found in cigarettes can reduce blood flow while damaging the walls of blood vessels. This makes quitting one of the most important steps in lowering blood pressure.  

• Limiting alcohol
  Because drinking alcohol is associated with high blood pressure, it may be advisable to reduce or even eliminate alcohol consumption to help lower blood pressure.

• Reducing sodium
  For some people who don’t process sodium well, eating no more than a teaspoon of salt per day may help lower blood pressure.

• Following the Dietary Approaches to Stop Hypertension (DASH) diet
  This diet emphasizes eating mineral-rich foods, such as vegetables, fruits, nuts, and seeds. This can help balance sodium levels and reduce blood pressure. 

• Doing cardio
  Cardiovascular exercise (the kind that raises heart rate) can strengthen the heart muscle, making it easier to pump blood using less effort. The American Heart Association recommends 150 minutes of moderate-intensity (or 75 minutes of vigorous-intensity) cardio per week. 

• Reducing stress
  While stress on its own may not cause high blood pressure, it can make it worse. Some effective stress-relieving techniques include yoga and meditation, talking to a therapist, and spending time out in nature. 

Medications

In some cases, medications may be necessary to control high blood pressure. There are many options available, which include:

• Diuretics.

• Beta blockers.

• Calcium channel blockers.

• Alpha blockers.

• Alpha agonists.

• Angiotensin-converting enzyme (ACE) inhibitors. 

• Angiotensin II receptor blockers (ARBs).

These medications work in different ways — for instance, diuretics work by “flushing out” sodium from the body, while beta blockers can work to reduce stress hormones, which helps the heart to beat more slowly and thereby reduces blood pressure. 

A doctor may recommend using medications either alone or in combination. It may take some trial and error before finding the right treatment approach.

Finding relief with HealthTap  

While high blood pressure may not cause headaches, it can do so in a hypertensive crisis, which is a medical emergency that requires immediate attention. 

If you or someone you know has a blood pressure reading above 180/120 in addition to symptoms such as mental confusion, blurred vision, and dizziness, it’s important to get help right away.

Aside from a hypertensive crisis, high blood pressure is unlikely to cause headache, though it can cause other symptoms and increase the risk for cardiovascular disease. 

If you have high blood pressure, HealthTap can connect you with a low-cost healthcare professional to provide a diagnosis and recommend lifestyle changes or medication.

Schedule an appointment with a HealthTap doctor today.