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How Light Affects Baby's Sleep

Updated: Nov 2, 2022

I once read that Matthew McConaughey stated that it was pretty simple having a baby because they "they crap, they sleep, and if they're crying they need to do one of the three and they're having trouble doing it. Real simple”.

I do agree with him on the first part of that statement but I do have to disagree on the second part. Any of those elements mentioned could be caused by a number of factors and that could be on their own or in combination with other factors. Being able to identify the issue could be simple but trying to determine the cause is all together much trickier.

There are so many factors which could be disrupting your Little Darling's ability to fall to sleep when they are tired. There could be a hormone imbalance, physical discomfort, they could be cold or too hot, over or under tired and to be honest, the possibilities as to why they can not sleep can seem never ending.

As a child sleep expert, I can say that the most common cause of poor sleep is light. Exposure to blue light has been shown to decrease baby’s feelings of drowsiness, increase the time it takes for them to fall asleep, decrease deep sleep, and affect their ability to stay asleep.

Light is everywhere and it is not something which we can change. Our ancestors were better at hunting and gathering during daylight hours while the light was bright enough for our eyes to pick up movement and colors. However, we also needed rest so it was better to sleep at night when we would not be at such a vulnerable disadvantage to our predators who can see better in the dark.

Over a long period of time, our bodies began producing hormones that help us fall to sleep when it begins to become dark (melatonin) and to provide stimulation when it it is starting to become light.(cortisol)

This actually worked magically for a very long time until a technological advancement that changed everything. In 1879, the electric lightbulb was invented. Before long, we had the ability for light 24/7 in all rooms in the house.

I know what you are thinking... "Well, what about candles? People did not live in the dark until the invention of lightbulbs!''. Yes, you are right but there is a very big difference between the light of a fire and that of an electric lightbulb.

The difference is wavelength...

I do not wish to get a little too nerdy on you here, (youcangetthescience-ystuffstraightfromNASAifyoureinterested.) but visible light comes in different wavelengths. Longer wavelengths appear red or yellow and shorter wavelengths appear white or blue.

As the lightbulb became more popular to the masses, and as the filaments evolved, we started reducing our long wavelength red or yellow light from candles in favour of the short wavelength blue light from electric bulbs.

Ok, so what does that matter? I need to take you back to our ancestors again to explain this... the light we get from the sun during the day comes directly down through the atmosphere, and that means it is not being refracted, which results in short wavelength AKA “blue” light.

Now when your Little Darling asks you why the sky is blue, that there is actually a big part of the answer. You are welcome :)

When the sun begins to set, it refracts off the atmosphere which stretches out the wavelength, creating red light. This is a big part of the reason why the sky turns red during the sunset.

Our bodies and brains have now evolved to pick up the cues from the sun and have started to produce hormones at the appropriate time of day. This is that the hormones are produced to either help us go to sleep or they help us wake up.

Once blue light was something which was now in every house, it is clear to see how our brains began to get a little confused. Our eyes would pick up daytime light well after sunset so our brains kept producing cortisol to keep us alerted which in turn blocks any release of melatonin and suddenly we found ourselves in a bit of a battle of hormones.

Let's fast forward nearly a hundred years to the invention of the television, which emits a huge amount of blue light. Then computers were invented, then smart phones and then the all time favourite of our young ones.. the tablet.

Question: If blue light harms melatonin production, can red light stimulate it?

The jury is still out on this debate actually. Some studies suggest that short-wavelength AKA red light can absolutely help stimulate melatonin production. However, other studies have shown that red light exposure resulted in similar or slightly less melatonin production than if baby just slept in the dark.

So, red light in a bedroom is not likely to improve baby sleep but it is not going to be harmful really. If you need a light in the nursery for nappy changes or night feedings, red light is the only light which you should be using.

Here are a few other light tips:

● Turn the lights in the house down (or off, if possible) around two hours before baby’s bedtime. I know this may not be fully possible but try to keep things as dimly lit as possible.

● Turn off all tablets, phones, Telephones, or any other electronic devices two hours before bedtime.

● Do not allow your childe to use electronic devices in their bed at bedtime.

● Cover over any lights emitted by devices in your baby’s room.

● Use a red or yellow light during baby’s bedtime routine.

I wanted to say, I do love technology! I absolutely love the convenience that my mobile provides, I watch TV, and I think that tablets do provide a great source of entertainment and educational aspects for our children. I am not suggesting that we revert to candlelight but I think it is important that we are all aware of how these devices can affect not just our babies sleep but also our own.


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