It happens so often that there is even a name for it. Being in the doctor's office makes people nervous; and when their blood pressure is taken, it is through the roof. High blood pressure readings triggered by medical personnel are called “white coat hypertension,” and they're so common that they are often written off.

Not so fast, say the results of a recent study. The elevated blood pressure seen in people with untreated white coat hypertension puts them at greater risk for heart disease and makes them twice as likely to die from heart disease as patients with normal blood pressure in the doctor's office.

The results add weight to the idea that blood pressure should not just be measured at a doctor's appointment. Check your pressure at home, at the drug store and in both arms.

“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,” said Jordana B. Cohen, one of the researchers and an Assistant Professor of Medicine at the Hospital of the University of Pennsylvania.

White coat hypertension is not likely to be taken lightly and left untreated any longer. People with white coat hypertension, who were prescribed blood pressure medications to treat their high blood pressure, had no increased risk of heart disease or cardiovascular-related death compared to those with normal blood pressure readings.

High blood pressure is pretty common among older adults. Nearly one in three have high blood pressure, often as a result of atherosclerosis, or narrowing of the arteries, which increases the pressure of blood flow and raises a person's risk for heart attacks and strokes.

A reading of 140/90 used to be the point at which a person was said to have reached the threshold for high blood pressure, or hypertension. The guidelines have been lowered to a top reading of at least 130 or a bottom one of 80.

The Penn Medicine team looked at 27 studies, involving more than 60,000 patients, that evaluated the health risks associated with hypertension. They found that patients with untreated white coat hypertension had a 36 percent increased risk of heart disease, 33 percent increased risk of death and 109 percent increased risk of death from heart disease.

The results add weight to the idea that blood pressure should not just be measured at a doctor's appointment. Out-of-office blood pressure monitoring, such as taking your blood pressure at-home and ambulatory blood pressure monitoring, which requires that one wears a portable device to record blood pressure over a 24-hour period, are just two recommendations. Drug stores and even some grocery stores also offer blood pressure monitors. Taking your pressure there should reduce the risk of white coat hypertension. It is also a good idea to check blood pressure in both arms.

“Our findings support the pressing need for increased out-of-office blood pressure monitoring nationwide, as it's critical in the diagnosis and management of hypertension,” Cohen said. The researchers advise patients with untreated white coat hypertension to change their lifestyles — quit smoking, reduce alcohol intake, and improve diet and exercise regimens.

Over-treating hypertension is dangerous to your health, too. Don't just rely on pills. Let your doctor know if you are on medication to lower blood pressure and depending on your specific situation, lose weight, cut down on salt and alcohol, and increase your activity level as much as you safely can.

The study is published in Annals of Internal Medicine.