A physician's presence may prompt changes to patients' nerve activity, interfering with accurate blood pressure readings, a small study published Aug. 9 in Hypertension, an American Heart Association journal, suggests.
The research evaluated the phenomenon known as "white coat hypertension," a rise in blood pressure in the presence of a medical professional. While not new, this study was the first to examine whether there are changes in a patient's sympathetic nervous system when a physician is or is not present during a blood pressure measurement.
Researchers from Italy evaluated 18 people, measuring their blood pressure, heart rate and nerve activity in the skin and skeletal muscle both before and after a physician was present. Fourteen of the participants were men with mild to moderately high blood pressure that was not being treated.
Findings showed patients' blood pressure and heart rate rose in the physician's presence. Changes in nerve traffic patterns in the skin and skeletal muscle also indicated a classic "fight or flight" reaction when around the physician.
When blood pressure readings were taken without a physician present, heart rate and nerve activity were different, with no indication of the fight or flight response.
Additionally, researchers found that on average, peak systolic blood pressure was 14 points lower when participants were alone compared to when a physician was present. The peak heart rate was also lowered by nearly 11 beats per minute when patients were alone.
"Measurements without the doctor's presence may better reflect true blood pressure values," said Dr. Guido Grassi, co-lead study author and professor of internal medicine at the University of Milano-Bicocca in Milan, Italy. While the "white coat hypertension" concept isn't new, "this just drives home the fact that we should be more conscious of how the blood pressure is taken in the clinic," Dr. Grassi added.
Researchers said follow-up research should include more women to evaluate potential sex differences, the effect of blood pressure medication, and whether the same effect is observed when patients have their blood pressure taken by nurses or other medical professionals.