What causes white coat hypertension?

Seeing a clinician, anticipating a reading, or worrying about what the result might show can activate the body's alert system. Hormones such as adrenaline make the heart beat more forcefully and can narrow blood vessels. The reading may therefore be higher in the surgery than it is at home. Generalised Anxiety Disorder can also make clinical settings feel more threatening, although white coat hypertension can occur without an anxiety disorder.

One high clinic reading does not show your usual blood pressure by itself. Home monitoring or ambulatory monitoring can compare readings across ordinary activities, rest, and sleep, helping a clinician decide whether the rise is limited to appointments.

Before a measurement, sit quietly with your back supported and both feet on the floor. Keep your arm relaxed at heart level, avoid talking, and allow the cuff to fit snugly. Follow the monitoring plan your clinician gives you, recording readings and the circumstances around them. Bring the monitor to an appointment if you want its technique or accuracy checked.

Do not stop prescribed blood-pressure medicine because readings are lower at home. Your clinician may use repeated home readings or a wearable monitor before deciding whether treatment is needed or adjusted.

Arrange a routine review if clinic readings remain high, home readings are repeatedly above your agreed target, or you develop headaches, dizziness, breathlessness, or ankle swelling. Seek urgent medical help for a very high reading accompanied by chest pain, severe breathlessness, weakness on one side, confusion, or a sudden severe headache. These symptoms need attention regardless of whether white coat hypertension is suspected.

Could home or ambulatory monitoring help confirm the pattern? What preparation should I use before checking my blood pressure? What readings or symptoms should prompt a same-day call? Could any medicines, caffeine, pain, or stress be affecting my results?