New Study Links Cellphone Use to Increased Risk of High Blood Pressure

If your cellphone conversations add up to 30 minutes or more a week, you could be increasing your risk for high blood pressure, according to a new study published May 3, 2023, in European Heart Journal — Digital Health.

Researchers found that talking on a mobile for a half-hour or more per week was linked with a 12 percent increased risk of hypertension (the medical term for high blood pressure) compared with talking less than 30 minutes.

“The number of minutes that people talk on their cellphone appears to matter for heart health, with more minutes adding up to greater risk,” says study author Xianhui Qin, MD, a professor at Southern Medical University in Guangzhou, China. But using cellphones long-term may not affect the risk of hypertension provided people talk for no more than 30 minutes per week, he says.

Previous Research on Cellphone Use and Hypertension Has Shown Mixed Results

Hypertension is a major risk factor for heart attack and stroke, and a leading cause of premature death globally. Nearly half of adults in the United States — 47 percent, or about 116 million people — have hypertension, according to the Centers for Disease Control and Prevention (CDC).

Hypertension is defined as a systolic blood pressure greater than 130 millimeters of mercury (mmHg) or a diastolic blood pressure greater than 80 mmHg, or being on medication for hypertension.

Mobile phones emit low levels of radiofrequency energy, which has been linked with rises in blood pressure after short-term exposure, but the findings have been inconsistent, according to the authors.

A study published in September 2022, for instance, found that higher cellphone use was associated with increased blood pressure in children and teens, although that study also included texting and gaming. But a study published in BMC Public Health in November 2022 found the opposite: Increased use was actually linked with lower blood pressure.

Using a Cellphone for Nearly an Hour a Day Was Associated With 25 Percent Increased Risk of Hypertension Compared With Those Who Rarely Talked

To better understand the relationship between making and receiving cellphone calls and new-onset hypertension, researchers included data from more than 200,000 participants in the UK Biobank.

Only people without hypertension were included in the study. Subjects were between the ages of 37 to 73, with an average age of 54. The UK Biobank is 95 percent white, and 62 percent of the participants were women; 88 percent were mobile phone users.

Information on cellphone use to make and receive calls was collected through a self-reported touchscreen questionnaire at baseline, including years of use, hours per week, and the use of a hands-free device or speakerphone.

To try to zero in on the impact of mobile phone usage and hypertension, investigators controlled for age, sex, body mass index, race, socioeconomic factors, family history of hypertension, education, smoking status, blood pressure, blood lipids, inflammation, blood sugar, kidney function, and use of medications to lower cholesterol or blood glucose levels.

Researchers followed participants for a median of 12 years, and during that time about 1 in 14 people, or 7 percent, developed hypertension.

• Mobile phone users had a 7 percent higher risk of hypertension compared with nonusers.
• People who talked on their mobile for 30 minutes or more per week had a 12 percent greater likelihood of new-onset high blood pressure than participants who spent less than 30 minutes on phone calls, and the results were similar for women and men.

Compared with participants who spent less than five minutes per week making or receiving mobile phone calls, these amounts of weekly phone call usage were associated with the following increased risks in developing hypertension:

• 30 to 59 minutes increased risk 8 percent
• 1 to 3 hours increased risk 13 percent
• 4 to 6 hours increased risk 16 percent
• more than 6 hours increased risk 25 percent

How many years people had been using a cellphone and whether they used a hands-free device or speakerphone didn’t affect the risk for high blood pressure, says Dr. Qin.

High Genetic Risk Coupled With High Phone Use Raised Risk the Most

Researchers used the biobank data to determine if participants had a low, intermediate, or high genetic risk of developing high blood pressure. The analysis showed that 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 percent higher likelihood of hypertension compared with those with low genetic risk who spent less than 30 minutes a week on the phone.

More Research Is Needed to Confirm Cellphone and Hypertension Link

This is an interesting study because talking on the phone is not something that we typically associate with risk of developing high blood pressure, says Jim Liu, MD, a cardiologist at The Ohio State University in Columbus, who was not involved in this research.

“I would still interpret these results cautiously because as the authors mentioned, there could still be several variables that confound the results of this study. The purpose of this study wasn’t necessarily to confirm a relationship between talking on the phone and hypertension, but really just to generate a hypothesis that would require more studies to evaluate,” says Dr. Liu.

The ”findings and the underlying mechanisms should be further evaluated in more studies,” wrote the authors. “In addition, our study focused only on making or receiving phone calls and did not investigate the impact of other uses of the mobile phone, such as texting, gaming or surfing the internet on health endpoints,” says Qi.

How Could Cellphone Use Trigger High Blood Pressure?

Although the study wasn’t designed to uncover why talking more on cellphones could increase risk, the authors had a few theories.

It could be that the position of the arm during phone use, combined with how the hand holds the phone, may increase sympathetic activity (the part of your nervous system that activates heart rate and blood flow). That could in turn trigger changes in the body that could raise blood pressure levels, says Qi.

“However, it's worth noting that our study found no significant link between using hands-free devices or speakerphones and new-onset hypertension — suggesting that the telephoning position alone may not fully explain the association between long-term mobile phone use and hypertension,” he says.

“People who talk on their phones more may use their phones more in general, and as the authors mentioned, higher frequency mobile phone use may be linked to more adverse mental health and sleep disorders, which can increase risk of hypertension,” says Liu.

Should People Limit Cellphone Use if They’re Concerned About Heart Health?

“We hope that our study contributes to a better understanding of the potential health risks associated with frequent mobile phone use and encourages further research in this area,” says Qi. It’s important for individuals to be aware of these findings and consider limiting their call time if they are concerned about their blood pressure levels, he adds.

Is this study enough to advise people to make sure they stay under the 30-minute threshold?

“I don’t think people need to go that far. Even the authors recognize that this study has limitations, and it merely proposes some hypothesis rather than establishing proof that talking on the phone for 29 minutes is any better than 30 minutes for blood pressure,” says Liu. There would need to be more in-depth studies looking into this specifically before we can make firm recommendations like that, he says.