Red Light, Morning Light and Children’s Sleep

Light is one of those parts of children's sleep that can easily get overlooked. Parents understandably spend a lot of time thinking about bedtime routines, naps and whether their child is getting enough sleep. But I often find myself talking to families about what is happening with light across the whole day, not just at bedtime.

As a Paediatric Sleep Practitioner and qualified Social Worker, I tend to look at sleep in the context of the whole child. Their age and development matter, but so do their sensory needs, relationships, environment, experiences and what is realistically manageable for the family. Light is useful because small changes can often be made without turning family life upside down.

I use red light at home with both of my own children, and I have one in my bedroom too. As bedtime approaches, our house gradually gets darker rather than staying brightly lit until somebody announces, "Right, bed!" There is good biology behind doing this.

Our circadian rhythm (essentially our internal body clock) responds strongly to light. During the evening, melatonin naturally begins to rise and helps signal that nighttime is approaching. Bright artificial light, particularly light with a higher proportion of blue wavelengths, can interfere with that signal.

If a child needs some light at bedtime, whilst we are reading their bedtime story and having the last cuddles of the day, a very dim red light is my preference. Red wavelengths generally have less effect on the circadian system than blue-rich light. The important word here is dim. I wouldn't recommend replacing one blazing bedroom light with a red one bright enough to guide aircraft onto a runway.

What dim red light can do is help create an environment that supports the body's natural preparation for sleep. For some children, particularly those who feel anxious in complete darkness or have additional sensory needs, having a small predictable light can also be much more practical than insisting on a completely dark room.

My social work background influences how I approach this. Advice has to work for the child and family in front of you. A child who has experienced trauma, separation or significant change may experience bedtime very differently from another child. Equally, a child with neurodiversity may have sensory preferences that make supposedly "perfect" sleep advice anything but perfect for them. We can support healthy sleep biology without losing sight of emotional safety, attachment and individual need.

For babies, any changes to the sleep environment should always sit alongside The Lullaby Trust's safer sleep guidance. A clear, flat, separate sleep space without pillows, duvets, bumpers, toys or other loose items remains important; lighting should never compromise those safer sleep principles. See my Guide to Safer Sleep for more information on this. 

Don't forget the other end of the day

Interestingly, when I'm working on sleep with families, bedtime isn't always where I want to make the first change. Sometimes I want to know what happens at 7 or 8 o'clock in the morning.

Morning light provides the body with a strong signal that nighttime has finished. Regular exposure to light during the morning and daytime helps anchor the circadian rhythm, which in turn supports the timing of sleep later on.

Opening the curtains is a good start. Getting outside is even better. Parents sometimes look out at a typically grey British morning and understandably think, What daylight?

But outdoor light doesn't need to feel sunny or particularly bright to us to be useful. Even on an overcast morning, outdoor daylight can be considerably brighter than normal indoor lighting. A brightly lit kitchen might look perfectly light to our eyes, while outside is still providing a much stronger light signal to the body's clock.

You don't need to turn this into another job on the parenting checklist either. Although it’s great to get out as soon as you can in the mornings, the school run counts, walking to nursery counts, standing outside while your toddler jumps in a puddle counts. 

Whenever it's practical, I encourage families to get some natural outdoor light into the first part of the day and continue having opportunities for daylight as the day goes on.

Then we gradually reverse things in the evening. Lights become softer. Screens and bright overhead lighting reduce where possible. The bedroom stays dark or, if light is genuinely needed, we use something very dim and preferably red.

Over time, these everyday cues help give the child's body a clearer distinction between daytime and nighttime.

But what about dark winter mornings?

Living in the UK means there is an obvious problem with the advice to “get morning light”. In the middle of winter, many families are up, dressed and halfway through breakfast before the sun has properly appeared.

If your child wakes while it is still dark outside, you don't need to keep the house dim waiting for daylight. Once they are up for the day, switch on the lights, open the curtains and make the environment feel like morning. We want a clear contrast between the low, warm lighting used before bed and a brighter environment after waking.

Then, once daylight does arrive, try to get outside when you reasonably can. This is particularly useful during the darker months because even a grey British winter's day can provide much more light than we typically receive indoors. 

I also wouldn't get too caught up in trying to achieve a perfect number of minutes at a perfect time. With children, consistency and practicality matter. If it is pitch black at 7am, use your indoor lights. If daylight appears at 8am, open the curtains and make the most of it. If everyone can get outside a little later, even better.

And there is a rather nice seasonal rhythm to this. In summer, we often have the opposite problem – plenty of evening daylight when we're trying to persuade a child's body that bedtime has arrived. Blackout blinds can be incredibly useful then, while winter is the season when I tend to think much more deliberately about getting children into daylight once it is available.

The principle stays the same throughout the year; we are helping the body notice the difference between day and night, rather than trying to recreate summer sunshine in December.

Final thoughts

Of course, light is only one piece of the sleep picture. Children's sleep is affected by age, development, temperament, sensory processing, physical health, emotional wellbeing, attachment experiences, routines and family circumstances. Some children need considerably more individualised support, and there is rarely much value in making parents feel they have failed because a generic sleep tip hasn't worked.

Still, light is one of the areas I come back to regularly in my work and in my own home. I like to think of it less as trying to make a child sleep and more as giving their body useful information.

Morning has arrived; the day is happening. Later, when the red light comes on and the house becomes quieter; night and rest is coming. The body is remarkably good at responding to those signals when we give it the chance.