Things you should know:
- Technology use in the evenings may delay bedtime and interfere with sleep.
- Using a bright screen for 1.5 hours or more can increase alertness.
- Not everyone is affected in the same way.
- Some forms of technology use and its activities may be better than others.
- In the evening, use technology in moderation. Switch interactive devices (e.g., phone) to passive devices (e.g., e-reader).
How can technology use affect us at bedtime?
Technology use before bed is linked to difficulties falling asleep and reports of increased alertness (1). This may be due to one, or a combination of the following:
- Bright screen lights, which can stop our bodies from releasing the ‘sleepy hormone’, melatonin (see our Melatonin fact sheet for more information), to prepare us for sleep (2).
- Activities on such devices can be stimulating and make us less ready to sleep (3).
- People can become absorbed and continue using technology beyond their usual bedtime, which is called bedtime procrastination.
How long is too long to spend in front of a bright screen before bed?
Studies have tested the effects of bright tablets (e.g., iPads) and laptop screens for up to 5 hours before bed. It seems that the natural evening rise in melatonin is not affected by 1 hour of bright screen light, but it is after 1.5 hours. Thus after 1.5 hours of technology use in the evening, people report feeling less sleepy. They also do better on mental performance tests and their brainwaves suggest increased alertness.
Repeated use of a bright screen over 5 days can delay the body clock by 1.5 hours. This means you consistently want to go to bed later and sleep in longer. This can be a real problem when you need to get up at a set time in the morning for school or work.
Do some forms of technology use affect sleep more than others?
Technological devices can be either interactive or passive.
Passive devices are those which need little to no input from the users. Examples include listening to music, reading an e-book, watching television or a movie.
With interactive devices, what is viewed on the screen changes with input from the user. For example, playing a video game is clearly interactive. To a lesser extent, so is surfing the web, messaging and making posts on computers, laptops, tablets and smartphones. Researchers propose that interactive technological activities are more harmful for getting ready for sleep compared to passive activities because they boost alertness.
Is everyone’s sleep affected by technology in the same way?
No. Some people are more affected than others. People who already have a tendency to delay their bedtime may be particularly affected by technology use, such as teenagers or people who are sensitive to light.
Research is yet to uncover all the different individual characteristics that explain why some people are more affected by technology use before bed than others. If you feel like you are particularly affected, you should consider avoiding technology before bedtime.
Can the alerting effects of screens be reduced?
Dim the screen as much as possible for evening use. Make use of any ‘night modes’ on devices as these change the light colour to avoid bright blue light, which may affect alertness more than other light colours. In many e-readers you can even invert the screen colour (i.e., white font on black background).
A free software program for PCs and laptops decreases the amount of blue light (which affects melatonin levels) in computer screens during the evening and increases orange tones instead. This program is called f.lux (https://justgetflux.com/).
What about watching television in the bedroom?
Many people enjoy reading a good book in bed, or listen to relaxing music or the radio before sleep. Those who report doing these passive activities in bed often have no trouble falling asleep, especially if the lights are dim or off. So considering the television is classed as a passive device, should it enter our bedrooms?
The answer is not clear. On the one hand, sleep experts talk about the benefits of keeping the bedroom as a sanctuary for sleep. They believe that electronic devices in the bedroom can easily be a distraction from sleep. We know that unsupervised teenagers can easily watch TV in their bedrooms till long past a healthy bedtime. On the other hand, we currently have no evidence that watching a TV in the hour before bed in the bedroom brings on sleep problems.
We do know, however, that relying on the TV being turned on while you fall asleep can mean you lose the ability to self-soothe yourself to sleep and thus may have trouble falling back to sleep when awake in the middle of the night.
What strategies can help regulate my child’s technology use?
Parents should try to restrict technology use to after-school or earlier in the evening. Plan quiet activities (e.g., board games, drawing, playing with toys, reading) closer to bedtime. This negotiation is more difficult in the teenage years. Try to encourage interactive technology use (e.g., video-gaming, smart phones) earlier in the evening, and use of passive technological devices (e.g., watching TV/movies, reading) in the lead up to bedtime. A certain level of accepting evening technology use is needed. After all, it has been found that about 97% of teenagers in the US use technology before bed (4).
Where can I find out more?
- (1) Gradisar, M., Wolfson, A. R., Harvey, A. G., Hale, L., Rosenberg, R., & Czeisler, C. A.(2013). The sleep and technology use of Americans: findings from the National Sleep Foundation’s 2011 Sleep in America poll. Journal of Clinical Sleep Medicine, 9(12), 1291-1299.
- (4) Johansson, A.E., Petrisko, M. A., & Chasens, E. R. (2016). Adolescent sleep and the impact of technology use before sleep on daytime function. Journal of pediatric nursing, 31(5), 498-504.