Reduced screen time reverses teenage sleep problems, study shows

Most young people are addicted to electronic gadgets, especially mobile phones and computers, which they use to browse the internet and communicate with their peers.

Aside from broadening their world view and making them tech-savvy, these digital devices are also robbing young people of much needed sleep.

This impedes optimal functioning of the brain and body processes that enhance the health status and wellbeing of individuals.

Affected people are more prone to mental health complications such as depression that are increasingly affecting young people.

They are also at risk of becoming obese and having low immunity, which predisposes them to other health complications.

To address this challenge, health experts recommend that young people should limit the use of electronic devices in the evenings.

According to research presented at the European Society of Endocrinology annual meeting (ECE 2019), sleep in teenagers can be improved by just one week of limiting their evening exposure to light-emitting screens on phones, tablets and computers.

The study – conducted by the Netherlands Institute of Neuroscience, the Amsterdam UMC and the Dutch National Institute for Public Health and the Environment - indicates that by simply limiting their exposure in the evening, adolescents can improve their sleep quality and reduce symptoms of fatigue, lack of concentration and bad mood after just one week.

Blue light is one of the colours in the light spectrum that can be seen by human eyes.

Display screens of computers, electronic notebooks, smartphones and other digital devices emit significant amounts of blue light that is only a fraction of what the sun gives.

Exposure to blue light emitted from these screens in the evenings is known to affect the brain's clock and the production of the sleep hormone (melatonin) hence resulting in disrupted sleep time and quality.

Aside from causing immediate symptoms of tiredness and poor concentration, the lack of sleep can also increase the risk of more serious long-term health issues such as obesity, diabetes and heart disease.

Previous studies have shown that sleep deprivation related to screen time might affect children and adolescents more than adults.

With this new study, researchers went further to fully investigate how real-life exposure to blue light from screens is affecting sleep in adolescents at home and whether the problem can be reversed.

They found that adolescents with more than four hours of screen time daily complained of more sleep loss symptoms.

In addition, they had an average 30 minutes later sleep onset and wake-up times compared to their peers who were exposed to blue light for only an hour in the evening.

Afterwards, the researchers assessed the effects of blocking blue light with glasses and screen exposure abstinence(banning use of electronic devices) during the evening on the sleep pattern of 25 frequent users.

Both initiatives resulted in sleep onset and wake up times occurring 20 minutes earlier, and a reduction in reported symptoms of sleep loss in previously affected participants, after just one week.

"Adolescents increasingly spend more time on devices with screens and sleep complaints are frequent in this age group. Here, we show very simply that these sleep complaints can be easily reversed by minimising evening screen use or exposure to blue light,” said Dr Dirk Jan Stenvers from the department of Endocrinology and Metabolism at the Amsterdam UMC.

He noted that based on the study findings, it is likely that adolescent sleep complaints and delayed sleep onset are at least partly mediated by blue light from screens.

"Sleep disturbances start with minor symptoms of tiredness and poor concentration but in the long-term we know that sleep loss is associated with increased risk of obesity, diabetes and heart disease. If we can introduce simple measures now to tackle this issue, we can avoid greater health problems in years to come," said Dr Stenvers.

Irrespective of these numerous challenges caused by screen time in the evenings, it is worth noting that not all blue light is bad for people.

It is well documented that some blue light exposure is essential for good health. Research has shown that high-energy visible light boosts alertness, helps memory or cognitive function and elevates mood.

Indeed, a procedure known as light therapy is used to treat seasonal affective disorder (SAD). This is a type of depression that is related to changes in seasons. It manifests in periods of dull weather and goes away during summer when sunlight is abundant.