I know, I know — that’s kind of a “duh” statement, right? We all know that sitting on our butts and putting our brains in neutral isn’t the best for our bodies, or for our minds. But even though correlation is not the same as causation (and most of the studies listed involve the former), they are fairly compelling.
The Stats on Screen Time
As of about a year ago, Nielsen reported that the average American watched 5 hours of television per day, while the US Bureau of Labor Statistics estimated a more modest 2 hours in 2016.
Meanwhile, this small British study estimates that young adults are on their smart phones one third of their waking hours, while this US study shows that we’re on our smart phones for five hours per day (as of early 2017).
It’s unclear whether there’s a material difference between TV and other forms of screen addiction (smart phones, tablets, etc), though certainly some of the consequences can be generalized.
Screen Time and Chronic Disease
This 2011 meta-analysis of eight studies established that TV viewing is, not surprisingly, associated with a 20% increased risk of Type 2 Diabetes and a 13% increased risk of cardiovascular disease. These two go together, of course, as part of metabolic syndrome—and this study also demonstrates that for every hour of watching television per day, diabetes risk goes up by 3.4%.
At least some of this is likely due to prolonged sitting associated with TV. But this study shows that you can’t compensate for lots of sitting with lots of exercise: even TV-watching adults who are already physically active (getting 150 minutes of exercise or more per week) were at increased risk of metabolic syndrome markers such as weight gain, hypertension, hyperlipidemia, and increased blood glucose levels.
This meta-analysis also associates prolonged TV watching (2 hours or more per day) with a 13% increased risk of all cause mortality.
TV vs Other Screens: Does It Matter?
One reason to think the above markers apply at least more to live television than to other kinds of screen time is the correlation between TV watching and junk food, perhaps due to all the commercials—though one could make the argument that prolonged sitting for any reason might have very similar effects.
Then there’s the whole issue of addiction—which might apply to television, the computer (video games or internet), or social media. According to Psychology Today, prolonged screen time and screen addiction is associated with atrophy of the brain’s gray matter (the part of your brain that actually thinks), leading to issues with impulse control, empathy, and compassion.
The Upshot
If you have a job that involves sitting in front of a computer screen (like almost all of us these days), you might be wondering what to do with this information. I had the same question.
So far, I haven’t seen evidence to suggest that it’s the screens themselves that pose a mental and physical health risk (beyond the blue light potentially disrupting melatonin production and therefore sleep—that is definitely true, so turn off screens 30 minutes before bedtime if you have trouble falling asleep).
Studies do seem to be pretty clear that prolonged television watching is bad for your health—whether that be due to lack of activity, eating junk, putting your brain in neutral, or all of the above. So limit your television time. If you have to sit down for long periods of time for work (in front of a screen or otherwise), try to get up and walk around at least once an hour for a few minutes. Vigorous exercise in the morning isn’t enough to completely eradicate the effects of prolonged sitting.
Studies are also clear that any addictive behavior involving a screen is negative for mental health. If you find yourself obsessively checking your smart phone, or compelled to revisit your last video game, or always surfing the internet, consider going on a short fast from the object of your obsession. (I suggest planning alternative activities in advance, though, so that the sudden void doesn’t drive you crazy. Set yourself up for success!)
