Beijing, May 5 (IANS): Talking on a mobile for 30 minutes or more per week is linked with a 12 per cent increased risk of high blood pressure compared with less than 30 minutes, according to a research.

Mobile phones emit low levels of radio frequency energy, which has been linked with rise in blood pressure after short-term exposure.

Almost three-quarters of the global population aged 10 and over own a mobile phone. Nearly 1.3 billion adults aged 30 to 79 years worldwide have high blood pressure (hypertension). Hypertension is a major risk factor for heart attack and stroke and a leading cause of premature death globally.

"It's the number of minutes people spend talking on a mobile that matters for heart health, with more minutes meaning greater risk," said Professor Xianhui Qin of Southern Medical University, Guangzhou, China.

The study, published in European Heart Journal-Digital Health, also showed that compared to participants who spent less than 5 minutes per week making or receiving mobile phone calls, weekly usage time of 30-59 minutes, 1-3 hours, 4-6 hours and more than 6 hours was associated with an 8 per cent, 13 per cent, 16 per cent and 25 per cent raised risk of high blood pressure, respectively.

While years of use and employing a hands-free device/speakerphone were not significantly related to the development of hypertension, genetic factors played a significant role.

The likelihood of developing high blood pressure was greatest in those with high genetic risk who spent at least 30 minutes a week talking on a mobile -- they had a 33 per cent higher likelihood of hypertension compared to those with low genetic risk who spent less than 30 minutes a week on the phone.

"Our findings suggest that talking on a mobile may not affect the risk of developing high blood pressure as long as weekly call time is kept below half an hour. More research is required to replicate the results, but until then it seems prudent to keep mobile phone calls to a minimum to preserve heart health," Professor Qin said.

To examine the relationship between making and receiving phone calls and new-onset hypertension, a total of 2,12,046 adults aged 37 to 73 years without hypertension were included.