Pediatric health practitioners have long cautioned parents about limiting the amount of television their children watch. Now, with the internet, smartphones, tablets, and portable gaming systems, children’s screen time has increased dramatically.

In 2011, the American Academy of Pediatrics (AAP) revised its recommendations about watching television to include these new media. The goal is not to label these devices or their contents as bad. Rather, it’s about providing parents with useful information to make informed decisions about how, when, and where they are used by their children, and offer strategies for families to minimize harmful effects on a child’s physical and emotional development.

The AAP suggests that for children under the age of two years old, watching television or use of any other electronic media serves no proven positive purpose. While some companies advertise their DVDs and other educational media products with claims that they will aid infants and young children with intellectual development, the fact is that no research indicates these materials help infants in any way with their maturation or capacity to learn. In fact, screen time can hurt an infant’s development by interrupting their concentration and focus in mastering a task.

For children ages 2 through 18, the AAP recommends limiting screen time to no more than two hours a day. That includes activities like watching TV programs or movies, playing video games, surfing the web, or going on social media sites. Using computers to write papers or do other homework assignments does not count toward that two hour limitation, as these exercises are intended to actively engage his or her mind as opposed to merely providing entertainment.

Concerns about obesity are among the chief health worries around children and screen time. The hope is that limiting television and computer use will curtail the unconscious snacking we all do when watching TV. One study revealed that while limiting TV viewing time did not increase the amount of physical activity in children, it did reduce their body mass index. This is because kids (and adults, for that matter) tend to eat more when watching TV, mainly because they aren’t paying attention to signals from their body indicating that they are full.

Another serious concern with having multiple TVs in homes and the proliferation of new media is the potential for increased isolation. When children are in separate rooms, there is little or no parental monitoring of the TV programs being viewing or the websites being visited on the internet.

Having just one television in a central location requires negotiations about what will be watched. It also provides an opportunity to have conversations about program content. Some families have a TV but only use it to watch DVDs. Others use a DVR or other recording technology to help limit screen time and skip over undesirable commercial messages.

Studies show that one-third to one-half of all American children have a TV in their bedroom. They may also be taking their smart phone or tablet to bed with them, leaving parents with little to no ability to know how much they’re watching or even what the content of the programming is.

Studies have also shown that older kids who have TVs in their bedrooms score lower on standardized tests. The possible reasons are up for debate. Perhaps it’s because it distracts from homework or side-steps opportunities for parental oversight. Too much screen time could limit young people’s ability to get a good night’s sleep. Regardless, we know the impact can be negative.

Parents have a number of ways to ensure their children’s screen time is limited to two hours a day. Creating a list of activity options or even an activity box, for example, will help when a child states, “I’m bored.” And keeping smartphones and computers in neutral locations during the night avoids unsupervised use.

Smartphones and computers are present in almost every aspect of our lives. But making sure that we balance their use with healthy lifestyle behaviors is a vital parental role.