White-coat hypertension, where a patient's fear of the doctor causes his blood pressure to rise higher than it usually is, seems to occur at home as well as in the doctor's office, according to European research.
The sphygmomanometer, which includes using an arm cuff, is often considered medicine's 'crudest' investigation. Known to be inaccurate in the doctor's office, it has largely been replaced by home ambulatory monitoring, which uses a portable electronic device that measures blood pressure at preset intervals over 24 hours.
Nevertheless, a study of 400 patients with high-blood pressure who took static cuff measurements at home, used a home ambulatory monitoring device and then had their blood pressure read in the doctor's office found that the best readings were taken at their doctor's.
Ironically, although some patients came up with more readings lower than the target range, enabling them to stop their medication, a similar number of patients had readings higher than target and had to go on to more than one drug.
Overall, final blood-pressure readings were higher at home than at the doctor's office, whether read by cuff or by ambulatory monitoring. So, perhaps the very act of brandishing the blood-pressure cuff, no matter who does it, is enough to make your blood pressure rise.
Before taking blood-pressure drugs, it may be prudent to have your blood pressure taken at home and at the doctor's office over many hours of the day, and days of the month, particularly as the weather and season, and even the solar activity can affect the final readings (JAMA, 2004; 291: 955-64).