White coat syndrome, or white coat hypertension, is when a person’s blood pressure reading is higher in a healthcare setting than at home. It is so named because doctors often wear white coats.

Some people who usually have normal blood pressure find that it spikes when the doctor takes a measurement. This condition is called white coat hypertension or the white coat effect. White coat syndrome can make a person’s blood pressure read higher than usual, potentially leading to an incorrect diagnosis.

However, in some cases, high readings at the doctor’s office may be a sign of an underlying blood pressure condition.

In contrast, some people experience masked hypertension, whereby their blood pressure tends to be lower in a healthcare setting and higher when elsewhere — for example, at home. This can give the false impression of a person with hypertension not having high blood pressure.

In this article, we explain what white coat hypertension is and why it affects some people. We also offer some tips on how to manage it.

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Hypertension, or high blood pressure, is a condition in which the force of the blood against the walls of the arteries in the body is too high.

The American Heart Association (AHA) notes that normal blood pressure levels are below 120 millimeters of mercury (mm Hg) for systolic blood pressure and below 80 mm Hg for diastolic blood pressure. Systolic and diastolic readings give the pressure during and between heartbeats, respectively.

Doctors usually define hypertension as a blood pressure reading of over 130/80 mm Hg.

Scientists do not know the exact causes of high blood pressure, but various factors can increase the risk. These include:

  • obesity
  • low levels of physical activity
  • smoking tobacco
  • alcohol consumption
  • stress
  • a high sodium diet
  • a family history of high blood pressure
  • older age
  • underlying health conditions, such as diabetes
  • genetic factors

Managing these risk factors may help some people keep their blood pressure in the healthy range.

White coat hypertension

White coat hypertension is high blood pressure that typically occurs only at the doctor’s office or other medical centers. It may relate to anxiety about healthcare visits.

A 2013 study found that 15–30% of people with a high blood pressure reading at the doctor’s office might have white coat hypertension.

It appears to be more common in:

  • females
  • older adults
  • nonsmokers
  • people with a recent diagnosis of mild hypertension
  • people who are pregnant

Masked hypertension

A person with masked hypertension will have a normal blood pressure reading at the doctor’s office but high blood pressure elsewhere. Factors that could contribute include mental stress at home, tobacco and alcohol use, and caffeine consumption.

In a 2015 study involving 3,027 people, 3.3% had white coat hypertension, and 17.8% had masked hypertension.

Some experts believe that white coat hypertension is due to the stress people experience when visiting a healthcare center. This stress triggers a reaction in the sympathetic nervous system, which plays a role in unconscious reactions, such as the function of the cardiovascular system.

However, there may also be underlying health problems in some cases.

Research has linked white coat hypertension to stiffness in the aorta, kidney damage, and cardiovascular problems.

In other words, it is unclear whether:

  • the stress of visiting the doctor is the only cause
  • there is an underlying health problem
  • a person with white coat hypertension has an increased risk of future problems

White coat hypertension may cause a spike in blood pressure, but not all doctors are convinced that this is the only cause of high blood pressure.

Some believe that white coat hypertension is a precursor to actual hypertension.

Stress and anxiety may play a role in high blood pressure, so people with white coat hypertension may still be more at risk of blood pressure-related issues.

In fact, a 2015 study found that people who had white coat hypertension were also more likely to experience cardiovascular issues. However, the risk appears to be small compared with that in those who have sustained hypertension.

It is essential, therefore, that doctors find a way to diagnose a person’s blood pressure accurately and start any necessary treatment.

Treating white coat syndrome can be tricky, as it can be hard for doctors to get an accurate reading of the person’s blood pressure to determine whether they have hypertension.

Typically, doctors do not prescribe medication to treat high blood pressure based on one high reading. This approach could lead to problems, such as hypotension, where a person’s blood pressure drops too low. Hypotension can cause dizziness and fainting, especially on standing up.

Instead, the doctor will take multiple readings. This may happen at a blood pressure clinic, or the person may use an at-home blood pressure monitor. In some cases, the doctor may suggest ambulatory blood pressure monitoring, which provides regular measurements over a 24-hour period.

A proper diagnosis is crucial to help treat or prevent hypertension. If the doctor concludes that the person has high blood pressure, they may recommend medication or lifestyle changes to treat it.

Learn how to check blood pressure at home.

Diagnosing white coat syndrome may be challenging, as it is often difficult to get an accurate reading. It may also be difficult to know whether a person’s high reading is due to chronic hypertension or being in a doctor’s office.

If the initial reading is high, a doctor may ask the person to come back in a few weeks for another reading. However, a person with white coat syndrome is likely to experience high blood pressure the second time.

In these cases, doctors may recommend that the person take their blood pressure readings somewhere else, using a home blood pressure monitor or an ambulatory blood pressure monitor (ABPM). An ABPM is a device that a person typically wears for 24 hours.

The device measures blood pressure, taking blood pressure readings throughout the day while a person is at home or following their daily routine. The doctor will compare the readings with those from their office to see whether the person needs treatment for high blood pressure.

If stress is the underlying cause of white coat syndrome, worrying about whether blood pressure will spike may be enough to cause it to do so during the reading.

The following tips may help a person stay calm and prevent inaccurate readings:

Relaxation techniques

Some relaxation techniques, such as breathing exercises or meditation, may help people stay calm before going into the doctor’s office.

People can try various techniques, including deep breathing, muscle relaxation, and guided imagery.

Ask to move somewhere else

People who find a doctor’s office intimidating could ask to move to a quiet room.

Ask questions

Becoming informed about hypertension and risk factors for developing it may help the person understand how likely they are to have high blood pressure. Some people find this reassuring.

Take time

It may help to arrive early and take time to do some relaxation exercises before going in to see the doctor. People who believe that they have white coat hypertension can discuss this with the doctor, who may have some ideas that will help.

If the doctor takes a blood pressure reading again at the end of the visit, they may find that it is lower. In some cases, people feel more relaxed toward the end of their appointment.

Experts believe that some people with white coat hypertension have a risk of future hypertension, cardiovascular complications, and organ problems.

However, having an incorrect diagnosis of hypertension can affect a person’s insurance rating. It can also lead to costly and unnecessary long-term treatment.

A thorough diagnosis is key to understanding the cause of hypertension. In cases of white coat hypertension, managing stress and anxiety levels may help. A doctor may also recommend using an ABPM to help get an accurate reading away from their office.

Anyone who suspects that they have hypertension should see a doctor, who can diagnose or rule out this condition.