How Screen Time Affects Our Sleep

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1. Please give a brief summary of your work.

Sleep is an essential part of our health and well-being. It is important for learning and memory, emotions and behaviours, and our general health. Despite this, it is often not made a priority and the total amount of sleep that we are getting is decreasing. Although there are potentially many reasons behind this trend, it is emerging that screen time – by way of watching television or using computers, mobile phones and other electronic mobile devices – may be having a large and negative impact on our sleep. Given that sleep is vitally important for development, the worrying trend of increased screen time at the cost of essential behaviours such as sleep should not be ignored. My laboratory focuses on many different aspects of sleep and health, including a new collaborative study investigating the use and impact of screen time on sleep and cognition in children and adolescents.

2. Describe your approach and broader findings.

The use of mobile phone and screen-based technologies has been steadily increasing, particularly in children and adolescents. The use of such devices, particularly in the evening prior to bedtime, has raised many questions regarding the impact that these devices may have on sleep, and health and development more generally. Relatively little research has been conducted on children and adolescents regarding this, therefore it is important that such issues are addressed. My current work includes an experiment aiming to determine the impact of screen time, in particular the light emitted from the screen while being used, on sleep, attention, and the sleep-wake hormone melatonin, in children and adolescents.


Children and adolescents between the ages of 10 and 16 are currently being recruited and tested in my sleep laboratory at the Illawarra Health and Medical Research Institute, University of Wollongong.


Each participant undergoes four nights in the sleep laboratory. The first night is an adaptation night in which the children get used to sleeping in the laboratory with all of the necessary equipment attached to measure their sleep. This is followed by three experimental nights in which they use an iPad prior to sleep each night (once with the iPad set to its highest brightness and no background room light; once with the night shift mode of the iPad switched on to reduce screen brightness and no background room light; and once with the night shift mode of the iPad switched on to reduce screen brightness and with background room light [40 - 60 lux]). Following each exposure, their sleep is monitored using polysomnography, subjective measures of sleep and sleepiness, as well as saliva samples to measure melatonin, are taken each evening and morning, and cognitive performance is measured each morning.


The current study will assess:

1. The effects of screen time and light on sleep architecture (e.g. sleep latency, sleep efficiency, distribution of sleep stages, etc)

2. The effects of screen time and light on brain activity both prior to sleep and during sleep

3. Analysis of subjective vs objective measures of sleep, giving an indication of the reliability of subjective sleep questions used in the GERoNiMO and COSMOS projects, two large and prestigious international studies investigating the possible health effects related to the use of mobile phone and wireless communication technologies

Outcomes and Significance

The study is currently underway, with results expected towards the end of 2017. In addition to providing valuable information for the GERoNiMO and COSMOS international research projects, the results of this study will provide outcomes that will contribute directly to health policy and the setting of international guidelines more generally.

3. What is the wider contribution, or impact, to your scientific field(s)?

If screen time is leading to insufficient or poor sleep in children, this could have large and negative ramifications. Sleep is incredibly important for healthy development, and not getting enough sleep is related to many poor physiological and psychological outcomes, such as impaired neurological and social functioning, learning difficulties, increased tension/anxiety/anger/moodiness, as well as increased symptoms of ill-health such as headaches, fatigue, and increased adiposity or weight gain. Therefore getting the balance right and promoting good sleep hygiene habits from an early age is important, and this study will contribute knowledge crucial for achieving this.

There are a number of ways in which screen time and technology could be impacting our children's sleep:

Bright Light

Many devices that are now routinely used by children emit bright light and the impact this has on sleep forms the main focus of the current study. Exposure to this light in the evening before sleep can increase alertness and can also disrupt the body’s naturally occurring circadian (or daily) rhythms by suppressing the release of the hormone melatonin.


The use of these devices can lead to delays in the time that children go to bed, resulting in shorter sleep overall.


Exciting content can engage the brain and lead to the release of hormones such as adrenaline which can reduce our ability to fall and stay asleep.

This first study will give an insight into the impact of one of these components - bright light - on sleep, with the hope to build on this and explore the other aspects of timing and content. This series of studies is important and incredibly timely given the rapid increase in use of screen devices by children, and will feed directly into recommendations and guidelines for a balanced and healthy approach to screen time in children.

4. Are there any potential ideas you would like to explore to take this research further?

As this is one of the first laboratory studies of its kind, and given that technology is increasingly being used in our daily lives, I plan to take this research further in a number of different ways. Firstly, there is a dearth of knowledge regarding the impact of such technology in the early years, so it is very important that we explore this issue in newborns and pre-school aged children given that they are at an extremely sensitive development and maturational stage of their lives. Secondly, this study is focusing on the impact that the light from screen-based devices may have on sleep, and there are other aspects of screen use, such as the timing, duration, and content, of which the impact should also be determined in the future.

5. Please share a link for researchers to access a relevant publication, data-set, or thesis.

Screen time and sleep in children:

How does screen time affect our sleep?:

Sleep On It: Busting myths and setting the record straight on what happens when we close our eyes:


Krista Hughes
almost 2 years ago

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