Happy Bedtimes – The effect of light and dark on your child’s sleep

Young boy fast asleep in his bedroom

Why is light so important for sleep?


Together Trust charity has provided expert knowledge on how light is the biggest external factor affecting your and your child’s sleep.

Your master body clock, which controls your circadian rhythms and keeps them regular, is totally dependent on light and dark.  Special cells at the back of your eyes, called photosensitive retinal ganglion cells, sense the morning light and the master body clock triggers the release of cortisol and other hormones to wake you up.  When darkness comes at night, our eyes sense the change in light levels and send a message to the master body clock which then sends a message to the pineal gland in your brain.  This triggers the release of melatonin.  Melatonin is the hormone often known as the ‘sleep hormone’ and it begins to be released about two hours’ before bedtime.

Young boy fast asleep in his bedroom

What are the issues with light now?

Going back millions of years, humans, like all other animals, tended to wake when it started to get light and sleep as it started to get dark.  Their sleep cycles were governed by the sun.  Now, we have so many light sources in our lives and so many different ways of manipulating light and dark, that it can play havoc with our sleep.

Many of the lights we surround ourselves with now are bright white, LEDs and blue light which is the light emitted from electrical devices like TVs, phones and tablets.  This type of light slows down the production of melatonin and makes it harder for your child to settle to sleep​.  Modern street lights are also bright white and seriously impact on sleep, especially if placed right outside your child’s bedroom!

In addition to all of this, your child’s eyes are much more sensitive to light than yours.  They have larger pupils, allowing more light in.  Their eyelids, especially babies’ eyelids, are thinner and more transparent.

Red light and amber/orange light (like the older street lights) have been shown to have little effect on melatonin production.  Their colour temperature mimics the sunset, signalling our bodies to relax and get some sleep.


What can you do to support your child’s sleep when it comes to light?

To support your child to sleep well, making simple changes with regards to light, can make a huge difference to how they settle to sleep and stay asleep.  It’s important to look at both the daytime and the night-time when it comes to light so we have put together some top tips for both below.

Top Tips for Daytime

  • Open your child’s blinds and curtains as soon after waking as possible.  This exposure to natural light will send the right message to your child’s brain that it is daytime and promote wakefulness from the very beginning of their day.  It will also keep the circadian rhythm ticking along nicely
  • Try and get out in the daylight as much as possible – most sleep specialists recommend at least 30 minutes per day.  Artificial lights at home, in nursery or in school do not give our brain the same messages as sunlight does.
  • If your child is really groggy on waking in the morning and finds it difficult to wake or get out of bed, you can buy alarm clocks that mimic a natural sunrise with the light growing brighter and brighter until the alarm actually goes off.
  • If your child spends a lot of time playing in their bedroom during the day or early evening, make sure their room is as brightly lit as possible so that the brain continues to receive the message that it is daytime and time to be awake

Top Tips for Evening Time

  • About two hours before bed, dim all the lights in the house and turn off lights that are not essential.  If your bathroom lights are bright during the routine bath before bed, turn them off and instead put the landing light on.
  • In your child’s bedroom, turn off overhead lights and instead use a bedside lamp with a shade. Click here to shop Lampshades 
  • Replace the bulb in your child’s bedside lamp with a red or orange one. You can also get colour changing bulbs so you can control what colour light they emit at different times of the day.
  • If your child uses electronic devices and they have a blue light filter (sometimes called ‘night shift’), make sure this is turned on two hours before bedtime and make sure all devices are turned off at least one hour before bed, including the TV.
  • Make sure your child’s bedroom is as dark as possible by using blackout blinds or curtains. Sometimes light will penetrate the gaps so you can also get removable black-out covers that stick to the windows to minimise this.  These are also quite handy for when you go away on holiday.  Check how much light is coming under the bedroom door too and use a draught excluder or rolled-up towel to block this. Click here to shop Blackout Curtains
  • If your child needs the bedroom door open, it’s best to turn the landing lights off.
  • For little ones who are scared of total darkness, we recommend small plug-in nightlights, especially ones that give a red or orange glow or glow-in-the-dark bedding sets.
  • Try to avoid projectors that project light onto ceilings as these will interfere with melatonin production and can be over-stimulating for some children
  • For some little ones, it is important to light a path to the bathroom during the night.  Motion-activated lights for hallways can deliver low levels of light only when this is needed, rather than all throughout the night.  You can also plug a small nightlight in on your landing if you have a plug socket there.

Sleep difficulties can often be due to lots of factors all working together but making a start in addressing light first may support your child’s ability to settle to sleep and stay asleep, giving you a good night’s rest too!


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