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Most people will admit that a visit to their doctor’s office may elicit anxiety, causing their blood pressure to rise. When blood pressure measurements are higher in the doctor’s office than at home, this phenomenon is known as white coat hypertension. The inverse scenario is also possible. You may have normal blood pressure readings in your doctor’s office but abnormal ones elsewhere, which is known as masked hypertension and is also an expression of white coat syndrome 

These examples support the recommendation that we should base blood pressure treatment decisions on multiple measurements in many different settings. For this reason, it is important to test your blood pressure at home, sometimes as frequently as once or twice a day, to get a sense of how your blood pressure fluctuates throughout the day. Providing your doctor with the results of your home blood pressure monitoring results can lead to a better diagnosis and treatment plan.  

What is white coat syndrome?

White coat syndrome is the term applied to any change in your blood pressure in response to being in a medical office. Three distinct diagnoses are based on how your blood pressure responds to being in the presence of a healthcare professional:  

  • White coat hypertension: A person is not taking medication for blood pressure and has high blood pressure in a medical office and normal blood pressure elsewhere.  
  • White coat effect: A person is taking medication for high blood pressure and has a high blood pressure reading in a medical office, suggesting their medication is not working. 
  • Masked hypertension: A person has normal blood pressure in a medical office but high blood pressure elsewhere. 

What is white coat hypertension?

Normal blood pressure is defined as less than 120/80 mm Hg. Anything above that threshold warrants investigation, even if the increase is only in your doctor’s office. Those with white coat hypertension may experience an increase in blood pressure by as much as 30 mm Hg simply by being in a medical office. Although an increase by 5-10 mm Hg is more typical.  

The diagnosis of white coat hypertension is made when:  

  • Blood pressure in the office is greater than or equal to 140/90 mm Hg 
  • Blood pressure out of the office is less than 135/85 mm Hg 

White coat hypertension is the reaction of white coat syndrome on your cardiovascular health.  

Blood pressure readings taken at your doctor’s office are commonly used to make treatment decisions. When your blood pressure readings only reflect your blood pressure in a medical office setting, not your daily life, your doctor may not have the best information possible to make a treatment recommendation for you. 

High blood pressure is the leading preventable cause of disability and premature death worldwide. It is normally diagnosed based on blood pressure readings taken at your doctor’s office. However, for many people, these measurements may not accurately reflect their average blood pressure. Their blood pressure may read high at the doctor’s office and normal in other settings.  

White coat hypertension was once thought to be harmless—a single episode of high blood pressure that did not reflect a person’s true blood pressure status. However, newer research on white coat hypertension has uncovered some interesting findings.  

White coat hypertension affects approximately 30% of people whose blood pressure meets the criteria for hypertension. Women, especially when pregnant, older adults, nonsmokers, and people who have been recently diagnosed with high blood pressure, are more likely to have high blood pressure in a medical office and normal blood pressure elsewhere.  

A misdiagnosis of high blood pressure can lead to unnecessary medical treatment that may last a lifetime. Blood pressure medications, like all medications, have side effects. These side effects may be more severe in older adults who take these medications. 

Home monitoring has identified five different hypertension phenotypes

Historically, high blood pressure was thought to be a single condition. With the introduction of home monitoring devices, researchers have been able to identify several blood pressure phenotypes: 

  • Normotensive: normal blood pressure inside and outside the doctor’s office while not on blood pressure medications 
  • Controlled hypertension: normal blood pressure inside and outside the doctor’s office while on medications 
  • Masked hypertension: normal blood pressure in the doctor’s office, but high blood pressure outside of the office
  • White coat hypertension: high blood pressure at the doctor’s office with normal blood pressure outside of the office
  • Uncontrolled hypertension: high blood pressure in all environments 

These variants of hypertension have been identified thanks to increased access to home blood pressure monitoring. Blood pressure measurements in a doctor’s office are a single point in time. To get the best possible diagnosis and treatment, it is important to measure your blood pressure at different times in the day and in different settings. This is why home blood pressure monitoring is an important adjunct to monitoring in doctor’s offices. Researchers are working to determine how each blood pressure phenotype affects the risk of damage to organs such as the kidney and eye and the risk for cardiovascular disease.  

How does home monitoring help providers better understand their patient’s blood pressure?  

With one in every five people who have an elevated blood pressure measurement in their doctor’s office eventually diagnosed with white coat hypertension, it is essential to fully understand how it impacts people’s health. Researchers from the University of Pennsylvania Perelman School of Medicine found that white coat hypertension was associated with a 36% higher cardiovascular disease and stroke risk. Those who were not taking medications for white coat hypertension were twice as likely to die from heart disease when compared to those with normal blood pressure. It is important to recognize this is a relative risk, not an absolute risk.  

Those who were diagnosed with white coat hypertension and started on medications did not have an increased risk of heart disease or death from cardiovascular disease.  

Jordana B Cohen, MD, MSCE, an assistant professor in the division of Renal-Electrolyte and Hypertension and a senior scholar in the Center for Clinical Epidemiology and Biostatistics and the lead researcher, said in a statement to Penn Medicine News, “We believe individuals with isolated in-office hypertension—those who are not taking blood pressure medication—should be closely monitored for transition to sustained hypertension or elevated blood pressure both at home and the doctor’s office.” 

Over time, even temporary increases in your blood pressure can have a long-term impact on your health. For this reason, researchers at Penn Medicine said that they strongly support the need for increased out-of-office blood pressure monitoring.  

How to overcome white coat hypertension?

More recent blood pressure guidelines emphasize the importance of taking and recording blood pressure readings outside of a medical office. The U.S. Preventative Services Task Force recommends that anyone who meets the criteria for hypertension have confirmatory blood pressure readings taken outside of the clinical setting.  

It is becoming clear that occasional blood pressure checks in the doctor’s office may not be enough to fully assess your risk for disease secondary to high blood pressure. Monitoring your blood pressure at home can help you track your blood pressure at various times of the day and in different settings. It can help provide feedback to support efforts you may make to control your blood pressure. And it can provide doctors with additional information to help them make a more accurate diagnosis.  

Taking your blood pressure at home and tracking your measurements reduces the risk of being misdiagnosed with high blood pressure and being put on unnecessary medications.  

Likewise, you decrease your chances of missing an accurate diagnosis of hypertension, a disease that could lead to long-term damage to your organs and cardiovascular system. 

How to get the most accurate reading at the doctor’s office

Try to get the most accurate blood pressure readings possible. In addition to making regular appointments in your doctor’s office to get your blood pressure measured, talk to your doctor to see if home blood pressure monitoring would help clarify your diagnosis.  

To get the most accurate reading in the doctor’s office, consider: 

  • Scheduling your appointment on a day when you will not be rushed 
  • Arrive a few minutes early to acclimate to the environment 
  • Ask to have your blood pressure taken in a quiet area 
  • Try deep breathing exercises before getting your blood pressure measured 

Once you are on blood pressure medications, it will probably be lifelong. Taking steps now to fully understand your blood pressure status and learn how to manage it can help you avoid heart disease later in life.  

Lifestyle changes such as smoking cessation, reducing alcohol intake, consuming a healthy diet, and adding physical activity as a part of your daily routine can help lower your blood pressure and decrease your risk of cardiovascular disease and stroke.  

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Leann Poston, MD, is a licensed physician in Ohio who holds an MBA and an M.Ed. She is a full-time medical communications writer and educator who researches and writes about medicine, education, and healthcare administration.