Internet use may harm teen health

Connecting with other teens online may be fun. But spending too much time on the Internet could lead to health problems, a new study reports. Heavy Internet use appears able to put teens at serious risk of high blood pressure, it finds.
As the term suggests, high blood pressure exerts extra outward pressure on vessel walls. With exercise, blood pressure increases. At rest, that pressure should return to a relatively low, background level. But in some people, it remains relatively elevated, even at rest.
High blood pressure in children and teens often continues into adulthood, says Andrea Cassidy-Bushrow, who led the new study. That’s a problem, she says. Persistent high blood pressure can trigger serious health problems, from kidney disease and memory loss to eye damage and heart disease or stroke.
Cassidy-Bushrow works at the Henry Ford Health System in Detroit, Mich. As an epidemiologist, she investigates causes of illness.
Obesity and diets high in salt are among factors known to boost blood pressure. But researchers worry that other, less obvious, factors also may play a role. Previous studies had linked screen time — watching television or playing on a computer — and high blood pressure. One possible reason: Teens on screens get less exercise, Cassidy-Bushrow says. But Internet use also has been linked to depression and obesity. And that’s for Internet use, specifically, not just screen time as a whole, she points out.
What might make Internet use more dangerous? It isn’t passive, like watching TV, Cassidy-Bushrow explains. There’s also the growing risk of cyberbullying, which can make it more stressful than other types of screen time.
What’s more, Internet connections are available in 98 percent of U.S. public schools. With cell phones and other mobile devices, the Internet can be as close as the touch of a button for most tweens and teens. And it’s available around the clock. Frequent Internet use has been linked to anxiety, addiction and social isolation. All of these are associated with high blood pressure in adults.
So the researchers recruited 331 adolescents, aged 14 to 17, to study whether Internet use might influence blood pressure in teens.
In the lab, the scientists measured each teen’s blood pressure, height and weight. They used some of these data to calculate each teen’s body mass index, or BMI. BMI is one way to look at whether somebody is over- or underweight. The teens also answered questions about how much time they spend on the Internet. This included both the number of hours per day as well as the number of days per week.
Nearly all of the teens had used the Internet during the week before their lab visit. Most reported accessing the Internet both at home and at school. Most also reported moderate to heavy Internet use. The researchers defined heavy use as two or more hours each and every day. Moderate use involved less than two hours a day on five to seven days a week. Light users accessed the internet for less than two hours a day and on no more than four days a week.
Four out of 10 teens used the Internet more than two hours every day. Nineteen percent of these heavy users had high blood pressure. That’s compared to just seven percent of light users. Another four in ten teens reported moderate use. These teens had moderately high blood pressure.
The findings appear in the October 2015 Journal of School Nursing.
“It’s an interesting study,” says Ellen Wartella. She is a psychologist at Northwestern University in Evanston, Ill. But, she points out, the study has a major limitation: The researchers measured blood pressure only once for each teen. However, she notes, “We know it varies considerably.” So a single data point for each person may not accurately reflect a teen’s average daily blood pressure.
Cassidy-Bushrow agrees that more research needs to be done. However, she adds, single blood-pressure readings have been used in other studies. For now, she recommends that school nurses screen students for high blood pressure and moderate to heavy Internet use.
Education and training for teens, teachers and parents also could help ensure that teens find a healthy balance in their online life, she says. That could go a long way in helping protect the health of people growing up in this digital age.