THE DETAILS: The researchers used data collected from extensive surveys filled out by 3,920 Scottish adults. One survey was devoted to psychological health and measured signs of depression and anxiety. Another measured how much physical activity the participants got, and how much time they spent doing sedentary activities like watching television. The researchers also collected data on physical health, such as body mass index, smoking behavior, and intake of fresh produce and alcohol.
Roughly 70 percent of the adults reported watching television for more than two hours per day, and 66 percent were classified as obese. Perhaps not surprisingly, longer television watching was associated with increased obesity, lower intake of fresh produce, and decreased physical activity. But increased television watching was also correlated with decreased psychological health. More specifically, as hours of television increased, so too did a person's level of depression and anxiety.
WHAT IT MEANS: As with kids who watch too much television, adults get stressed out and depressed from too much screen time and sedentary behavior. "We are seeing that too much sedentary behavior has more and more harmful health effects," says the study's lead author Mark Hamer, PhD, senior research fellow in the department of epidemiology and public health at University College London. And in this case physical exercise didn’t seem to help, though past research has shown it improves mental health. In Hamer's study, people who watched more than two hours of television a day but got the recommended 30 minutes of exercise per day were still more likely to feel depressed and anxious. Hamer say it's unclear why TV seems to have this effect on people. The bottom line? "Try to limit sedentary TV time as much as possible," Hamer says.
If you watch a lot of TV and are trying to cut back, it may help you to know these other ways TV watching can affect human health and development:
• It can make you gain weight. A study published last year found that adults who watched more than three hours of TV per day were more likely to gain weight. Fortunately, the added weight from watching too much TV was reversible. Those who cut their TV time to less than two hours a day lost a half-pound a week.
• It can increase risk of teen pregnancy. Research on adolescents has found that highly sexual content on television has an influence on teens' risk of becoming pregnant. Even younger kids aren't immune to adult content. A study published last year found that kids ages 6 to 8 who watch adult programming tend to start having sex earlier than kids who don't.
• It delays development. When the television is turned on, parents talk to their children 7 percent less of the time, found another study. This may not have a big effect on older kids, but when babies and toddlers don't hear their parents’ voices, it takes longer for them to learn how to talk, the researchers found. Relatedly, children develop better verbal skills when they're interacting with a live person, as opposed to the TV.