What Is White Coat Syndrome?

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High blood pressure, or hypertension, puts people at risk for heart attacks, stroke, and other serious health conditions, maybe even dementia. Diet, exercise, and medication can help people lower their blood pressure, but a common condition called white coat syndrome may complicate the diagnosis. Fifteen to thirty percent of people whose blood pressure falls in the hypertensive range when measured in a doctor’s office are thought to have white coat syndrome.

BrainFacts.org spoke with Andrew Sherwood, who studies the causes and management of hypertension and heart disease at Duke University School of Medicine, about what’s known about this still poorly understood condition.

What is white coat syndrome?

White coat syndrome refers to the situation where a patient’s blood pressure readings are high when measured in a medical environment, such as during a routine check-up at the doctor’s office, but their blood pressure is normal in most other circumstances.

Is it a problem?

It is a problem in two different ways. First, if doctors repeatedly observe a patient’s blood pressure as in the hypertensive range, they may diagnose hypertension and prescribe antihypertensive medications, which their patient then takes unnecessarily. Secondly, there is evidence that patients with white coat hypertension are at higher risk of adverse cardiovascular events than individuals whose blood pressure is normal both when measured at the doctor’s office as well as during their typical daily routine. In other words, the white coat syndrome does not appear to be an entirely benign condition.

How do stress and anxiety affect blood pressure?

Numerous studies, both in controlled laboratory conditions as well as those conducted during individuals’ normal daily routines, show that stress is associated with transient increases in blood pressure that can be surprisingly large. The magnitude of stress-induced increases in blood pressure appears to be a characteristic of the individual that often generalizes to a wide range of different kinds of psychosocial stressors. White coat syndrome may be a marker of a tendency for a patient’s blood pressure to increase in response to a variety of sources of daily stress.

Anxiety is also a characteristic that has been linked to the white coat syndrome. Anxious patients may be especially concerned about the possibility of serious health issues when they are being evaluated in a medical environment, which could cause them to perceive it as a stressful situation, leading to a rise in blood pressure.

How can physicians recognize white coat syndrome and accurately measure blood pressure in affected patients?

In all people, blood pressure varies markedly throughout the day. Typically, it is highest in the morning and lowest while we sleep at night. Superimposed upon this circadian rhythm are short-term variations in blood pressure associated with physical activity and psychosocial stress. Therefore, the gold standard for assessing blood pressure is a portable device called an ambulatory blood pressure monitor. A patient wears the monitor for 24 hours and blood pressure measurements are taken three or four times per hour during when the person is awake and twice an hour during nighttime sleep. A blood pressure profile taken in this way allows a physician to clearly recognize the white coat syndrome and determine the optimal approach to managing a patient’s blood pressure.

The 24-hour ambulatory blood pressure profile is a far better indicator of the risk of developing cardiovascular disease, as well as the likelihood of adverse cardiovascular events, including heart attack and stroke, than blood pressure measured in the clinic. Despite unequivocal evidence supporting the value of ambulatory blood pressure monitoring in routine patient care, in the United States, it is employed relatively rarely. Its importance, value in patient care, and overall cost-effectiveness are more appreciated in Europe, where it is widely used in several countries.

Where ambulatory blood pressure monitoring is not an option, home blood pressure monitoring performed by the patient using relatively inexpensive blood pressure monitors may help the physician recognize the presence of the white coat syndrome.

This Ask an Expert was answered by Andrew Sherwood as told to  Jennifer Michalowski for BrainFacts.org.

About the Author

Jennifer Michalowski

Jennifer Michalowski writes about scientists and their discoveries, exploring topics ranging from ancient evolution to the newest insights about the brain.