The Dangers of Too Much Screen Time

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Poor dietary habits and a largely sedentary lifestyle have been the combination that has played perhaps the most significant role in the obesity epidemic. Increasing amounts of screen time promote this combination, sometimes in unforeseen ways.

What Is Screen Time?

“Screen time” refers to all the time we are increasingly spending looking at screens of all types—including computer and tablet screens, phone screens, television screens, gaming screens, and the like.

By all accounts, the amount of time spent by both children and adults in front of various screens has increased exponentially in the past few decades.

Screen Time Leads to Unhealthy Behaviors

If you are reading this while sitting down at your computer or other device, you may want to stand up. That is because several studies have now shown that the damage done to the cardiovascular and metabolic systems of the human body by sitting for prolonged periods of time may actually be worse than that of cigarette smoking!

In one study of over 13,000 Spanish university graduates, television viewing was found to be directly associated with premature death from any cause.

Multiple studies have found that a sedentary lifestyle is associated with obesity. One such study found that more sitting at baseline was associated with increases in body mass index (BMI) over time. This holds true for children and adolescents as well.

Another study of adolescents who were followed every 6 months from age 14 to age 18 found that greater screen time was associated with adolescent obesity.

Other studies have shown that too much time in front of the television promotes unhealthy eating habits. In an analysis of over 1,000 children, investigators found that those who watched television for two to six hours per day were more likely to have a higher BMI than those who watched less TV or spent an equal amount of time on a computer or playing video games.

It is not yet clear why television time seems to have a different effect from computer time, but experts hypothesize that TV time in particular is associated with poorer dietary choices (think of all the chips, microwave popcorn and other high-calorie, low-nutrition foods that often accompany TV watching).

One study found that video games that promote physical activity have the potential to increase movement and burn more calories compared to sedentary video games.

Screen Time and Lost Sleep

Several studies have now established that the blue light emitted by LED screens suppresses melatonin production and thereby interferes with the ability to fall asleep. In turn, chronic sleep deprivation is associated with weight gain and overeating.

To optimize your chances of falling asleep and staying asleep, make it a habit to turn off all screens at least an hour before going to bed. Since the light emitted from computer, phone, and tablet screens can be particularly harmful when it comes to suppressing melatonin and disrupting circadian rhythms, plan to turn those devices off two or more hours before bedtime.


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