Ana Blazic Pavlovic/Shutterstock
Source: Ana Blazic Pavlovic/Shutterstock

It’s hard to believe that the smartphone was introduced by Steve Jobs less than a decade ago, in January of 2007. Today, most teenagers, and just about every adult, has a smartphone. On average, Americans use smartphones for approximately 4.7 hours a day according to a recent study by Informate Mobile Intelligence in Seattle.

Another report, from the American Academy of Pediatrics, found that children ages 8 to 18 use some type of electronic device approximately seven-and-a-half hours daily. Media use among children of all ages has increased exponentially in the past decade and it appears to be disrupting their sleep patterns dramatically. 

A study released this week found that smartphone use combined with social networking is overriding our natural circadian rhythms. These effects are showing up most blatantly at bedtime. Smartphone use during the day obviously leads to excessive screen time, but bedtime use exacerbates sleep disturbances.

Among other side effects, poor sleep hygiene reduces cognitive function and increases depression risks. Sleep hygiene is defined as, 'habits and practices that are conducive to sleeping well on a regular basis and having full daytime alertness.'

Most of us are guilty of bringing our smartphone to bed with us. Like many people, I sleep with my iPhone on a nightstand next to my bed. I hate to admit it, but having my phone in another room while I'm sleeping would give me some weird type of separation anxiety. I know it's absurd... But, statistically the research says I'm not alone. Most people sleep with their phone. Do you sleep with your smartphone next to your bed, too? 

Sometimes, I forget to turn off the ringer and my phone will ding in the middle of the night. All too often, I'll wake up and start texting with someone in a different time zone. Then, of course, I can't fall back to sleep. Whenever my smartphone disrupts a good night's sleep, the next day I always feel like my synapses are firing out of whack and my brain is unsynchronized. 

One reason for this type of insomnia could be that the "blue light" emitted by a smartphone is intensified when you're viewing it in a dark room. The short wavelength of blue light can have a strong impact on sleep hygiene because it delays the release of melatonin, which makes it more difficult to fall asleep.

Smartphone Use and Sleep Disorders Exacerbate Depressive Symptoms 

A 2015 study from University of Basel reported that teenagers' smartphone use during the night is associated with an increased risk of sleep problems and depressive symptoms. The researchers found that only 17% of smartphone owners turned their devices off—or put their devices on silent mode—when they were in bed.

VectorLifestylepic/Shutterstock
Source: VectorLifestylepic/Shutterstock

Teenagers who own smartphones spend more time online during the night, which can dramatically affect their sleep. The researchers found that, teenagers with smartphones tend to watch videos, surf the internet, and text with friends late at night. From a public health perspective, the worst news from this study was that teenagers who used smartphones at night had an increased risk for poor sleep hygiene and showed symptoms of depression.

Therefore, sleep experts recommend that teenagers—who suffer from sleep disturbances and subsequent daytime drowsiness—should be encouraged by parents to switch all of their digital media devices off at least one hour before bedtime.

Texting After Bedtime Impacts School Performance in Adolescents

A January 2016 study, from Rutgers University, found that texting at night affects teens' sleep and their academic performance. In fact, students who turned off their digital devices or text messaged for less than 30 minutes after lights out, performed significantly better in school than those who messaged for more than 30 minutes after lights out.

Stefano Cavoretto/Shutterstock
Source: Stefano Cavoretto/Shutterstock

Whether or not you are a teenager, excessive nighttime texting may be to blame for reduced cognitive performance and feeling lethargic during the day. The recent Rutgers study was the first of its kind to link nighttime texting habits of American teenagers with sleep hygiene and academic performance. 

The researchers found that students who texted longer in the dark slept fewer hours and were more tired during the day than those who stopped messaging and turned off their phones when they went to bed. This is common sense, but it's nice to have empirical evidence to back up something most of us have probably realized from our own life experience. 

In a statement, study author Xue Ming, professor of neuroscience and neurology at Rutgers New Jersey Medical School, said,

"During the last few years I have noticed an increased use of smartphones by my patients with sleep problems. I wanted to isolate how messaging alone—especially after the lights are out—contributes to sleep-related problems and academic performance.

When we turn the lights off, it should be to make a gradual transition from wakefulness to sleep. If a person keeps getting text messages with alerts and light emission, that also can disrupt his circadian rhythm. Rapid Eye Movement (REM) sleep is the period during sleep most important to learning, memory consolidation and social adjustment in adolescents. When falling asleep is delayed but rising time is not, REM sleep will be cut short, which can affect learning and memory.

We need to be aware that teenagers are using electronic devices excessively and have a unique physiology. They tend to go to sleep late and get up late. When we go against that natural rhythm, students become less efficient."

Ming suggests that educators recognize the sleep needs of teenagers and incorporate sleep education into their curriculum. "Sleep is not a luxury; it's a biological necessity. Adolescents are not receiving the optimal amount of sleep; they should be getting 8-and-a-half hours a night," Ming said. "Sleep deprivation is a strong argument in favor of later start times for high schools—like 9 a.m."

Smartphones Are Disrupting Circadian Rhythms Around the World

Courtesy of NASA
Source: Courtesy of NASA

Everybody has an internal biological clock that dictates our circadian rhythms and the fluctuations within our bodies that are directly tied to our planet's 24-hour day. Circadian rhythms are controlled by a grain-of-rice-sized cluster of 20,000 neurons behind the eyes called the Suprachiasmatic nucleus (SCN). The SCN is regulated by how much light, particularly natural sunlight, is taken in by specific cells in the retina.

Circadian rhythms are the prime driver of our sleep schedules. Even with the advent of artificial light and the modern day 9-to-5 work schedules, our circadian rhythms seemed to be staying in tune with the Earth's rotation. However, digital technologies are playing an even bigger role in disrupting our natural sleep patterns in the smartphone era than most experts anticipated.

A new study on worldwide sleep habits from University of Michigan used smartphone data to examine how age, gender, amount of light, and someone’s homeland affects the amount of sleep individuals around the globe are getting in our modern and hyperconnected world.

The May 2016 study, "A global Quantification of “Normal” Sleep Schedules Using Smartphone Data," also examined national trends about specific times people in different countries generally go to bed, and when they wake up.

The researchers were motivated to use smartphones to track international sleep patterns because so many people around the globe are currently sleep deprived. In a statement, lead author Daniel Forger said,  

"Across the board, it appears that society governs bedtime and one's internal clock governs wake time, and a later bedtime is linked to a loss of sleep. At the same time, we found a strong wake-time effect from users' biological clocks—not just their alarm clocks. These findings help to quantify the tug-of-war between solar and social timekeeping."

A recent CDC study found that across the United States, one in three adults are not getting the recommended minimum of seven hours sleep. According to the CDC, sleep deprivation, increases the risk of obesity, diabetes, high blood pressure, heart disease, stroke, and stress. The new data from Forger and colleagues also revealed that:

  • Middle-aged men get the least sleep, often getting less than the recommended 7 to 8 hours.
  • Women schedule more sleep than men, about 30 minutes more on average. They go to bed a bit earlier and wake up later. This is most pronounced in ages between 30 and 60.
  • People who spend some time in the sunlight each day tend to go to bed earlier and get more sleep than those who spend most of their time in indoor light.
  • Habits converge as we age. Sleep schedules were more similar among the older-than-55 set than those younger than 30, which could be related to a narrowing window in which older individuals can fall and stay asleep.

Conclusion: Turn Off Your Smartphone One Hour Before Hitting the Sack

Humans have evolved to spend roughly one-third of our lifetime sleeping. Ideally, you should sleep about 8 hours a night, which adds up to 122 days of sleep per year. Your mind, body, and brain will function optimally at a basic two-to-one ratio of wake-to-sleep. For every two hours you're awake, you need about one hour of sleep. By the time you are sixty years old, this would add up to twenty years spent sleeping, and about five solid years in REM sleep.

Smartphones are disrupting sleep patterns for people around the globe. Even if you manage to get six hours of sleep a night, you're still building up a sleep debt, according to researchers. Regardless of your age, the best advice seems to be to turn off your smartphone (and all other digital devices) one hour before bedtime to minimize the "blue light" exposure to your SCN which disrupts circadian rhythms and sleep patterns.

To read more on this topic, check out my Psychology Today blog posts, 

© 2016 Christopher Bergland. All rights reserved.

Follow me on Twitter @ckbergland for updates on The Athlete’s Way blog posts.

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