High blood pressure, also called hypertension, and low blood pressure, known as hypotension, are both serious medical conditions. But what is more dangerous: high or low blood pressure? Both affect the pressure of blood against the walls of your arteries. This pressure is essential for moving blood through the body. When it is too high or too low, the risk of illness increases. But one of them causes much more harm over time.
How Blood Pressure Works
Doctors measure blood pressure in two numbers. They call the top number called systolic pressure. It shows how much pressure your blood is exerting against your artery walls when the heart beats. The bottom number is diastolic pressure. It shows the pressure when the heart is resting between beats.
A person is considered to have high blood pressure if their readings are consistently above 130/80 mm Hg. Low blood pressure is typically defined as a reading below 90/60 mm Hg.
How Common Is Hypertension?
Hypertension is very common. According to the World Health Organization (WHO), around 1.28 billion adults aged 30 to 79 have hypertension worldwide. About 46% of adults with hypertension do not know they have it. In the United States, the Centers for Disease Control and Prevention (CDC) reports that 47.7% of adults had high blood pressure in this country-wide study from 2021 to 2023. That’s nearly one in every two people.
These numbers are rising. This is partly because of aging populations and poor diets. A diet high in sodium (salt), fat, or processed food increases the risk. So does lack of exercise. Smoking and stress also play a role.
Health Risks of High Blood Pressure
Hypertension often shows no symptoms. That is why doctors call it “the silent killer.” It quietly damages the body over time.
Long-term high blood pressure makes the heart work harder. It causes blood vessels to become stiff or narrow. This can lead to heart attack, stroke, kidney failure, or even dementia.
A major global study called the Global Burden of Disease project found that high blood pressure was the leading risk factor for death in 2019. Hypertension results in up to 10.8 premature million deaths that year. This included more than half of all strokes and nearly half of all heart disease deaths.
In the United States alone, hypertension contributes to more than 670,000 deaths each year, according to CDC data from 2023.
One long-term study from the Framingham Heart Study showed that people with blood pressure above 140/90 mm Hg had double the risk of heart failure compared to those with normal levels.
How Common Is Hypotension?
Low blood pressure is less common. A 2024 preprint study using U.S. national health data found that about 7.6% of adults had hypotension. It is more common in young women and older adults.
Unlike hypertension, hypotension usually causes symptoms right away. These include dizziness, fainting, blurry vision, and fatigue. The most serious risk is falling. In older adults, this can lead to injury and even death.
Some people experience low blood pressure due to dehydration, medication, or blood loss. Others may have it from medical conditions like heart failure or Parkinson’s disease.
When Is Hypotension Dangerous?
While hypotension is often mild, it can be dangerous. A 2020 study in Age and Ageing found that people over 75 with blood pressure under 130/80 mm Hg had a higher risk of death—especially if they were frail or had multiple health problems.
But hypotension is usually not the cause of death itself. It is often a symptom of another problem. It rarely causes long-term organ damage.
Why Hypertension Is More Dangerous
Hypertension is more dangerous for three key reasons.
First, it is more common. About 1 in 2 adults in many countries have it, compared to fewer than 1 in 10 with hypotension.
Second, it causes more deaths. It is linked to heart attacks, strokes, kidney failure, and dementia. These conditions often develop silently over years.
Third, many people with hypertension do not know they have it. They do not treat it. That allows damage to build up.
Hypotension, on the other hand, is usually noticed quickly. People with low blood pressure tend to get symptoms right away. This means they are more likely to seek help before serious harm happens.
Who Is at Risk from Each?
People with hypertension are often adults over 40, especially those who are overweight or inactive. It is also more common in African Americans and people with a family history of heart disease.
Hypotension mostly affects older adults who take medications that lower blood pressure, especially diuretics or beta-blockers. It also affects people with nervous system disorders or severe infections.
What You Can Do
To avoid problems, it is important to check your blood pressure regularly. A reading that is too high or too low should be followed up with a doctor.
For high blood pressure, lifestyle changes help. These include cutting down on salt, eating more fruits and vegetables, quitting smoking, and exercising regularly. If needed, there are many medications that can help lower blood pressure safely.
For low blood pressure, treatment depends on the cause. Drinking more fluids and standing up slowly can help. In severe cases, medication may be needed.
