Is it dangerous to sleep with your smartphone?. Image 1.

Molly Mirhashem


Is it dangerous to sleep with your smartphone?. Image 2.

Erin Lux


Whether it’s waiting up for a response to an unanswered text, replying to work emails long after the end of the business day, or aimlessly scrolling through Instagram, even the most disciplined among us can be found at least occasionally—if not regularly—tucked into bed with our smartphones tightly in hand or nestled under our pillows.

In a July 2015 Gallup survey, 63% of respondents admitted to keeping their smartphones close by while sleeping. But aside from the generalized guilt that comes with procrastinating before bedtime, is it actually dangerous to sleep with your smartphone? We turned to several experts in fields like chemistry, sociology, and psychologyto identify and explain the risks associated with sharing your bed with your electronic devices.



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Lauren Hale, Ph.D.

Associate Professor of Preventive Medicine, Program in Public Health, Stony Brook University School of Medicine  

Depending on studies you use, somewhere between 50% and 90% of teenagers are not getting the sleep they need. And you cannot study teenage sleep without considering the pervasive role of technology.

There are three basic mechanisms through which screen time can impair sleep: First, time displacement—when one is occupied on a screen this takes away from time spent doing other activities, especially something as all-consuming as sleep. Second, there is psychological stimulation due to the social, emotional, and sometimes violent nature of the content of many screen-based activities. And finally, there is the role of light coming from the screens which has both circadian and alerting effects on the body.

Last year, I conducted a systematic literature review on the association between screen time and sleep in youth. In the 67 studies from around the world, over 90% of them identified an adverse association between screen time and sleep. While there was some variation across types of devices used, the vast majority studies of all types of devices (televisions, computers, smartphones) showed delayed bedtimes and shorter total sleep time with more screen time. While the studies on screen time and sleep are relatively consistent, there are numerous outstanding questions regarding the magnitude of consequences on sleep and health, individual variation in susceptibility, and preventative steps that teenagers and families can take to improve their sleep and well-being in this rapidly evolving technological landscape.





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Brian Zoltowski, Ph.D.

Assistant Professor, Department of Chemistry, Southern Methodist University

For electronic devices like laptops, phones, anything with a LED or LCD display, the problem is that they produce a large amount of artificial blue light. Our natural cue to what time of day it is, primarily to know when morning is, is blue light. By exposing ourselves to large amounts of blue light late at night, we are giving our bodies a cue that it’s time actually to wake up instead of go to sleep. This can lead to defects in our circadian rhythm, and it’s been shown that when we have our biological clock out of phase with the natural day-night cycle outside, that can lead to increases in the rates of diabetes, cancer, heart disease, and even depression.




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Emerson Smith, Ph.D.

Sociologist, Clinical Research Assistant Professor of Internal Medicine, University of South Carolina, School of Medicine, CEO and President, Metromark Research

Having a smartphone, tablet or laptop in bed has an impact on health and social relationships. One health issue is having a light on a screen, whether the screen is on a smartphone or a television, when the body needs sleep. The light creates a “jet lag” effect, resetting the body’s internal clock, making it difficult to get needed sleep, and leading some to become dependent on sleeping aids.

Another health issue for smartphones in bed is the twisting of the head and body to read the screen, leading to aching muscles and bones. Smartphone use involving lowering of the chin while walking, standing, or sitting, can create stress and pain in the body. Laying on your side to read the screen in bed for long periods of time while viewing or entering text also contributes to muscle and skeletal stress and pain.  

Use of cell phones to talk or text while in bed can also destroy relationships between people sharing the same bed or the same house. Such bedtime use coupled with daytime use can also create a round-the-clock dependency on the phone for social interaction while reducing or eliminating the mentally healthy benefits of face-to-face communication.

For children and teenagers, the dependency on smartphone use, whether for games or for communicating, during what would normally be sleep time can harm the child’s emotional and physical health as well as performance at school. Such dependency also disturbs effective  relationships between child and parent as well as between the child and siblings.

Smartphone use is detrimental to health and social relationships—while driving, while walking, while sitting, and in bed. Humans are not meant to be multi-taskers, especially when one task takes precedence over other tasks that are more supportive of the preservation of life, health, and face-to-face relationships.




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Larry D. Rosen, Ph.D.

Research Psychologist, Professor Emeritus, California State University, Dominguez Hills, George Marsh Applied Cognition Laboratory

The reason why we need sleep is manyfold. Our brain does major housekeeping while we’re asleep; it’s almost as active as it is during the day. And what it’s doing is three major processes: one is called consolidation: practicing things that happen during the day, that your brain deems important. Secondly, unimportant stuff that happens during the day gets pruned away. And thirdly, your spinal column opens up a tiny bit and allows more spinal fluid to wash through your brain, cleaning out the debris that was left behind by all your thinking.

All three of these tasks are pretty critical. When you get a good night’s sleep, these all happen in synchrony. You go through four sleep phases, getting deeper into sleep, then you go into REM sleep—and this process repeats all night long. If you don’t sleep well and aren’t well-rested, the process gets all messed up: you miss sleep phases, or you go right into REM sleep if you’re in a lot of sleep debt. And that means that some of those processes—like consolidation, pruning, and cleaning out all the toxins—don’t happen. And since most of us don’t get enough sleep, this is normal. But it affects our memory, our ability to process, and pretty much everything else.

We have discovered in our work that there are two major issues that cause this: one is a cognitive or mental component, and the other is an emotional or affective component. The cognitive component is what’s called executive function—it’s the stuff that takes place in front part of your brain, making decisions, paying attention, working on things, stopping yourself from making impulsive decisions. The affective, emotional part is anxiety—an anxiety about missing out. It’s the anxiety that comes when you realize that you haven’t checked Facebook in 15 minutes, or you haven’t commented on someone’s Instagram photo. So if we get anxious, then we have to check in. It turns out that both of these components (bad executive function and anxiety about missed connection) combine to increase smartphone usage during the day, in the last hour before you go to sleep, and when you get up to check it in the middle of the night. This is mainly bad for you because it activates your brain—if you checked someone’s Instagram and you want to comment, all of a sudden your brain is hyped up and not going to sleep.

In addition, all of those devices give off blue light, which activates cortisol and inhibits the release of melatonin, which is really critical because it puts you to sleep. All of this overuse of technology leads to a lousy night’s sleep, which leads to your brain not functioning well




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Mariana Figueiro, Ph.D.

Professor, Lighting Research Center Light and Health Program Director, Rensselaer Polytechnic Institute

It depends on the kind of device and how long people are being exposed to it, but there’s clearly a potential for suppressing melatonin in the evening, which is the hormone we start producing a couple of hours prior to bedtime. Melatonin is essentially a nighttime or darkness signal, telling us it’s time to go to bed. So, if you delay the onset of that signal in the evening, by being exposed to too much light coming from those devices, you may be delaying sleep times. Then, if you have a fixed wake up time and can’t sleep in to compensate, you are experiencing sleep deprivation. Even if you filter the light of the display or somehow protect yourself from it, it may be just as bad, because you’re still depriving yourself of sleep by staying awake to use the device. 

Sleep deprivation has been linked to a series of things—it’s been shown that after five consecutive days of five hours of sleep instead of eight hours, people can become pre-diabetic or become hungrier. In the short-term, you become sleepier during the day, and you may reduce daytime performance. And then long-term, you may have more serious consequences, such as increased risk for obesity, diabetes, cardiovascular disease, and even increased risks of cancer. I’m not saying that these self-luminous displays cause cancer—that would be a big statement. But you want to minimize disruption of circadian rhythms and the curtailment of sleep as much as possible.




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Mary A. Carskadon, Ph.D.

Professor of Psychiatry & Human Behavior, Brown University

Sleeping with these types of devices is not too wise, primarily because of their association with disrupted sleep. From TVs to computers to tablets and smartphones, young children’s sleep seems to be very compromised. Whether these devices disrupt sleep because of noise, light, social interactions (or the promise of them), such devices take a toll. The downsides of insufficient and disrupted sleep are many, including learning and memory deficits, cognitive impairment, metabolic difficulties, depressed mood, disrupted immune function, and excessive fatigue—to name a few.

A counter argument, however, goes that people who suffer anxiety when parted from electronic devices will have disrupted sleep if they don't have the devices in their bedrooms and preferably in their hands.




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Chad Ruoff, MD

Clinical Assistant Professor, Psychiatry and Behavioral Sciences, Stanford Center for Sleep Sciences and Medicine

These devices provide too many opportunities to stimulate the mind around bedtime. We should not be performing stimulating tasks close to bedtime, regardless of whether or not we are in the bed. We should strive to keep a buffer zone between daytime activities and sleep—the bed and bedrooms should be reserved for sleep and sex. We should not be watching TV while laying in bed, and we should not play on devices such as smartphones, computers, and other electronic devices while in bed.