For a long while, I’ve been toying with the idea of taking a modified digital sabbatical — by which I mean abandoning my electronic devices the moment the workday ends — and for a long time, I’ve made excuses for why I cannot: Crucial work emails pile up after hours; Twitter is one of the most efficient ways for media people to stay on top of the news cycle; I actually like tweeting and lingering on Facebook and staring at mindless viral videos.
But the reasons to do it have lately become very persuasive. High among them: the health benefits. And here’s an especially seductive one: An electronic Sabbath may help you lose weight.
It sounds inane, like the stuff of the late-night local news (Does your iPad make you fat? Details at 11.) But there’s increasing evidence that the longer we spend in front of our glowing, pinging, dinging devices — especially after dark — the more dysregulated our metabolisms become. It’s not just that our devices encourage a more sedentary lifestyle. It’s that they agitate us and flummox our hormones, which in turn affects our sleep — and when we’re sleep deprived, we lunge for comfort foods.
A study from Rensselaer Polytechnic Institute, for instance, has shown that spending two hours in front of a “back-lit” electronic gadget (like an iPad or a laptop — anything emitting blue light, essentially) suppresses the production of melatonin, the hormone regulating our circadian rhythms, by about 22 percent. This deficit can in turn lead to delayed sleep, disrupted sleep, early waking times — you name it. Last year, the International Journal of Obesity looked at 632 U.K. adolescents and found a strong positive correlation between evening technology use and increased Body Mass Index. (Correlation doesn’t mean causation, obviously, but as the researchers concluded, their findings practically cried out for a controlled experiment: “If confirmed, improving sleep through better management of technology use could be an achievable intervention for attenuating obesity.”) Many studies of adolescents over the last five years, whether they’re looking at kids from low-income parts of Oakland to middle-class central France, have noted some kind of link between screen time, sleep loss, and physical health.
The link between sleep loss and weight gain is fairly straightforward, summarized by a one-two punch: If we don’t sleep enough, our bodies produce more ghrelin, the hormone that tells us to eat, and less leptin, the hormone that tells us to stop. Sleep deprivation also seems to trigger cravings for junk food — researchers have seen evidence of just how much by showing volunteers images of chocolate and potato chips while undergoing functional MRIs — and handicaps our prefrontal cortexes, the parts of our brain that under non-sleep-deprived circumstances would tell us that gorging on chocolate and potato chips is a lousy idea. (The prefrontal cortex, among many things, governs our ability to reason, to plan, and to regulate our impulses.)
It’s already fairly well established that people consume more food when watching television. Recently, researchers at the University of Bristol found the same among those who eat in front of their computers, though their sample was small and the design of their study was a bit eccentric (they fed 44 subjects the same meals at lunchtime; those who ate while playing computer solitaire were apt to eat twice as many cookies 30 minutes later as those who ate far from a glowing screen). The theory, whether it’s television or a desktop: You remember eating when you’ve made a separate activity out of it; you don’t if you’re doing something else, and therefore misgauge your appetite.
Yet it’s increasingly difficult for Americans to unplug. Last winter, The Journal of Clinical Sleep Medicine reported that nine out of ten of us use a technological device in the hour before bed. (In 60 percent of those cases, it’s the TV, but that’s in aggregate; for Americans under 30, it’s cell phones, which the researchers deemed much more disruptive.) According to a Pew study from 2010, 65 percent of Americans sleep with their cell phones on or next to their beds (for people 18–29, that number jumps 90 percent.) And in 2012, a poll by Harris Interactive found that 54 percent of Americans look at their phones while lying in bed.
None of which is to say that curtailing email and Facebook and Twitter use will make us lose ten pounds. But it cannot hurt, at the very least, and reminds us that all of our cells, be they inside our bodies or in the palms of our hands, could use a good rest.