Mobile Devices, or Adolescent Sleep Thief

Problems related to sleep, such as difficulty in falling or remaining asleep, are frequent among teenagers. Several factors have been described that could lead to alterations in sleep patterns. The recent increase in the use of screen devices such as smartphones, tablets, laptops, TV or videogames has been suggested to be one of the main determinants of sleep.  

In a new ISGlobal study published in Environment Research, we conclude that those teenagers with a higher use of the phone or the tablet have a lower quality of sleep and their sleep pattern is more fragmented. 

In a new ISGlobal study, we conclude that those teenagers with a higher use of the phone or the tablet have more trouble falling asleep and their sleep pattern is more fragmented

The study was performed with over 250 teenagers between 17 and 18 years of age that live in Menorca (Spain) and form part of the INMA Project cohort. The teenagers answered a questionnaire on their use of mobile devices and sleep quality, and the latter was objectively measured during one week with the ActiGraph bracelet monitor.

It is important to define what is meant by quality of sleep. The National Sleep Foundation defines it as sleeping at least 85% of the total time in bed, falling asleep in 30 minutes or less, waking up no more than once per night, and falling back asleep in 20 minutes or less. 

In epidemiological studies, the quality of sleep is often assessed by asking “How would you rate your sleep?” Participants have five possible answers: very poor, poor, average, good, very good. This is a suitable and easy way to evaluate sleep quality and suspect if a child is not fulfilling the conditions cited above. 

Many studies indicate that the use of screen devices affects child and adolescent sleep. However, the mechanisms underlying this association are still not clear and several hypothesis exist

Many studies indicate that the use of screen devices affects child and adolescent sleep. However, the mechanisms underlying this association are still not clear and several hypothesis exist:

Inappropriate content

Today, even the youngest children are familiar with the use of mobile devices, internet and different apps. Most often, they use these devices alone or without parental  surveillance, and are likely to be exposed to content that is not appropriate for their age and that may lead to difficulties in falling asleep.  

Late sleeping hours

In addition to watching TV after dinner, using screens in bed also delays sleep time.  As a result, adolescents sleep less hours than needed during weekdays, when they need to wake up early for school, university or work. Drowsiness and dysfunction during the day is one of the main complaints by children and adolescents that report lack of sleep.  

Mental Arousal

The idea that one should do relaxing activities and prepare body and mind before going to sleep, is not new. Screens stimulate the brain very much and, when used before sleeping, can retard sleep onset.

Exposure to blue light

Screens emit blue light, i.e. visible light with wavelengths between 380 and 500 nm. Blue light suppresses melatonin production two-fold more than any other wavelength, and alters the circadian rhythm. This can change our sleep patterns and affect our health.

Exposure to radiofrequency electromagnetic fields

Some electronic devices emit radiofrequency electromagnetic fields. Experimental studies have shown that exposure to these fields alters brain waves during sleep, but the clinical relevance of this is still unknown. In addition, these effects have not been confirmed with observational studies due to inconsistent results. Thus, this hypothesis needs to be further explored.

Almost all previous research, including our own study, has been performed using a cross-sectional approach. This means that screen use and sleep quality are asssessed at the same time. This is a great limitation to understanding causality and long-term effects.

Although different statistical techniques can be applied to try to establish causality (i.e. confirm that the use of a new technology leads to sleep alterations), solid conclusions cannot be made because other factors may interfere and bias the association in question.

In any case, cross-sectional studies performed to date have helped establish that new technologies affect sleep in the short-term. The long-term implications remain an open question.

Cross-sectional studies performed to date have helped establish that new technologies affect sleep in the short-term. The long-term implications remain an open question

These cross-sectional studies, together with the exponential increase in the use of these devices over the last years particularly among children and adolescents, are important public health messages that support the need for longitudinal studies (i.e. evaluating the use of devices and sleep at different moments of child and adolescent development). This will be an important step to understand the potential long-term effects of screen devices in a world where they have become an indispensable part in many people’s lives.

Following the results of our study, the current scientific evidence, and the existing public health recommendations, we propose the following steps to improve the quality of our sleep:

• Limit the time of screen use during childhood and adolescence (television, mobile phones, tablets, computers, or videogame consoles)
• Avoid screen exposure when bedtime approaches. If not possible, use a blue light protection screen
• Keep mobile devices outside the bedroom. If not possible, put them in airplane mode

It is important to note that these are not general recommendations and can vary according to the age. Furthermore, there is not enough scientific evidence yet to draw specific conclusions for each device and activity (current recommendations group everything under “screen devices”). However, we believe that watching television is very different to sending text messages or using the tablet, which means that specific health recommendations for families, children, adolescents, schools and pediatricians are needed for each type of device and age.

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