Mark Bridge writes:
I was on the radio for a few minutes this morning. Nick Ferrari on LBC 97.3 FM was talking to me about a recent survey that noted a rise in blood pressure when people received calls on their mobile phones. As I waited to go on-air, a producer asked me what I thought. “Storm in a teacup”, I said. Well, it seemed better than “Makes my blood boil”.
At least LBC spent a few minutes looking into the story, which came from the annual American Society of Hypertension meeting in San Francisco. That’s more than some newspapers have done. The Daily Mail chose a headline of “Talking on a mobile phone can give you high blood pressure due to the stress it can cause”. Yet the research wasn’t about talking but answering. The Telegraph has “Mobile phones cause blood pressure to rise”, which is worryingly vague. Why am I being cynical about these stories? To start with, the research was conducted on people who were taking medication for already-diagnosed hypertension. The purpose was to see whether answering a phone call during blood pressure monitoring would affect their readings.
Yes, their blood pressure was affected by receiving a call. Readings rose rose from an average of 121/77mmHg to 129/82. That wouldn’t worry me too much - after all, the NHS says any reading below 130/80 is considered to be normal - but it’s a much bigger deal if you’re taking medication and your doctor wants a consistent, accurate measurement.
Dr Giuseppe Crippa, who heads the hypertension unit at Guglielmo da Saliceto Hospital in the Italian city of Piacenza, conducted the research. He’s quoted as saying “This phenomenon might lead to misinterpretation and overestimation of the real patients’ blood pressure status. We believe that it is important to advise all patients to turn off their phone before entering the doctor’s office.”
That’s sensible advice. In fact, I’d say that’s the appropriate conclusion to be drawn at the moment.
After all, the study was of just 94 people... all of whom were receiving phone calls during blood pressure monitoring from a number they didn’t know. Interestingly, people who used their mobiles more than 30 times a day weren’t as dramatically affected as those who used their phones less.
Would a similar result have been noted if the patients had witnessed an unexpected event when watching television - perhaps during a news programme or an action film? Would a fixed-line phone have had the same effect? I don’t know. That’s something for another study.
Health professionals often talk of ‘white coat syndrome’ or ‘white coat hypertension’, which refers to an increase in blood pressure experienced by some patients when they’re in a clinical setting. It sounds as though an unexpected phone call can have similar effects.
In fact, I wonder what happens to blood pressure when people read about health scares in newspapers?
[Crippa Giuseppe , Zabzuni Dorjan, Cassi Antonino, Bravi Elena; Mobile Phone Calls Acutely Increase Blood Pressure Levels in Hypertensive Subjects [abstract]. Journal of Clinical Hypertension 2013;15 Suppl 1 :74]