Cell Calls During BP Readings May Skew Results
Interruption can cause spike in systolic pressure, study found
The result: By comparing readings taken with and without incoming calls, the team found that patients' systolic numbers (the top figure in a blood pressure reading, indicating blood pressure as the heart contracts) went up "significantly" whenever the patients answered their phones.
Patients who had indicated relatively heavy routine cellphone usage (30 or more calls per day), however, experienced a less steep rise in their systolic numbers during incoming calls. Since heavy users tended to be younger, the team theorized that a greater cellphone comfort level among younger patients may protect them from the cellphone dynamic.
Incoming calls had no impact on patients' diastolic numbers (the bottom figure in a reading, indicating blood pressure while the heart is at rest), nor did patients' overall heart rates shift when the cellphone rang.
The team concluded that patients should be advised to turn off their cellphones whenever and wherever they have a blood pressure reading, to ensure accuracy.
"It is noteworthy that the great majority of the patients recruited for this survey were not used to turning off the mobile phone, even during a medical examination, and easily answered the calls even when an automated device was measuring blood pressure," Crippa said.
"Therefore, we believe that it is important to advise patients that the unnecessary and exaggerated use of cellphones can increase, at least temporarily, their blood pressure," he said.
Dr. Gary Schwartz, a professor of medicine at the Mayo Clinic College of Medicine in Rochester, Minn., said the issue is not the disturbance of a cellphone call, but rather any disturbance in general.
"I wouldn't look at this study and say cellphones are bad for you," Schwartz said. "But American Heart Association standards call for the need to be quiet, whether you're getting your blood pressure measured at a doctor's office or at home.
"Just engaging in conversation, whether or not it's on the phone, can raise the numbers and give an inaccurate reading," he said. "It's the same principle behind why we don't measure a person's blood pressure while they're playing tennis. What we want is for patients to be quiet and at rest."
Crippa and his colleagues are scheduled to present their findings Wednesday at the American Society of Hypertension annual meeting in San Francisco. Research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.