"White coat hypertension" is the name given to the very common condition -- occurring in up to 20% of patients -- in which a person's blood pressure is abnormally elevated when it is measured in the doctor's office, but is within the normal range the rest of the time. White coat hypertension is usually attributed to the anxiety which one often experiences when in a doctor's office.
Specifically, white coat hypertension is diagnosed when blood pressure measurements in the doctors' office average higher than 140/90 mmHg, while blood pressure measurements outside the office reliably average less than 140/90 mmHg.
It therefore seems likely that in many cases -- given the cold, sterile and harried environment of most doctors' offices these days -- white coat hypertension may not reflect anxiety, but rather, the infeasibility of actually achieving a state of "quiet restfulness" in a place such as that.
In any case, current evidence suggests that the cardiovascular risk associated with white coat hypertension lies somewhere between the risk seen in normal individuals and in individuals with straightforward hypertension.
At present, antihypertensive drug therapy is generally not recommended for patients with white coat hypertension, though it is reasonable to recommend appropriate lifestyle modifications aimed at reducing the blood pressure, as well as steps to reduce cardiac risk in general. Read about treating hypertension.
It seems highly probable that not all people with white coat hypertension are the same. Some likely have real hypertension (and need to be treated), while others do not. This is why many experts now recommend that patients with white coat hypertension undergo ambulatory blood pressure monitoring (ABPM). ABPM is a way of assessing a person's blood pressure throughout a one- or two-day cycle. Using ABPM to diagnose hypertension eliminates the need to simulate a condition of "quiet rest" in a doctor's office, where, more commonly, the prevailing sense is one of quiet panic. ABPM may allow the physician to make a more reasoned assessment of whether a person with white coat hypertension has true hypertension, and needs to be treated.
# Ohkubo, T, Kikuya, M, Metoki, H, et al. Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h ambulatory blood pressure monitoring 10-year follow-up from the Ohasama study. J Am Coll Cardiol 2005; 46:508.