The Surprising Light Connection That Could Be Disrupting Your Baby’s Sleep

When we think about what babies need, the basics are usually pretty simple: they eat, they poop, and they sleep.

Figuring what they need in a given moment is usually straightforward. But figuring out why they’re struggling to do it—especially when it comes to sleep—is another story entirely.

When your baby has trouble falling asleep or staying asleep, the reasons can be endless: they might be overtired, not tired enough, too hot, too cold, teething, uncomfortable, overstimulated, or still developing the independent sleep skills that help them settle and resettle on their own.

And one big (often overlooked) culprit I see over and over again in my work as a pediatric sleep consultant? Light.

Why Light Plays Such a Big Role in Baby Sleep

Light—especially blue light—has a powerful influence on our sleep-wake cycle. Research shows that blue light exposure can:

• Delay feelings of drowsiness

• Increase the time it takes to fall asleep

• Reduce deep, restorative sleep

• Cause more night wakings
  

To understand why, it helps to go back—way back—to our ancestors. Humans evolved to be awake and active during daylight hours (when light helped us see clearly) and to rest when it was dark (when we were less effective and more vulnerable to predators).

Our bodies adapted beautifully: when the sun went down, our brains began producing melatonin, the “sleep hormone.” When the sun came up, melatonin production slowed and cortisol—the “alert” hormone—took over.

This worked perfectly… until 1879, when Thomas Edison introduced the electric lightbulb.

The Big Shift: From Firelight to Lightbulbs

You might be thinking, “But people had candles and lanterns before that—didn’t they use light at night already?” Yes, but here’s the difference:

• Firelight produces long wavelengths (reds and yellows).

• Electric bulbs—especially as they evolved—produce shorter wavelengths, aka blue light.
  

Why does that matter? Sunlight during the day is full of blue light, which signals to our brains, “It’s daytime! Stay awake!” When the sun sets, the light shifts to longer red wavelengths, which signal, “It’s time to wind down.”

When we started bringing blue light into our homes after dark, our brains got confused. We were sending a “daytime” signal long after sunset, delaying melatonin release and making it harder to fall and stay asleep.

The Modern Challenge: Screens Everywhere

Fast forward another century or so, and along came televisions, computer monitors, tablets, smartphones, LED lights—all packed with blue light. And now our babies and young children are growing up in a world where bright screens are everywhere.

The Red Light Question

If blue light delays sleep, can red light improve it?

The research is mixed. Some studies suggest red light may support melatonin production, but others show that while it’s much less disruptive than blue light, it doesn’t significantly increase melatonin levels compared to darkness.

Here’s my take: If your baby is already sleeping in a dark room, you don’t need to add a red light to “help” them sleep. But if you need light for nighttime feedings or diaper changes, red (or amber) light is absolutely the way to go.

Light Management Tips for Better Baby Sleep

Here are a few simple changes that can make a big difference:

• Turn off all screens at least two hours before bedtime.

• No electronics in bed—ever.

• Cover or tape over any tiny lights from baby monitors, sound machines, or other devices.

• Use warm-toned light for bedtime routines like bath time and reading.

My Bottom Line

I love technology. My phone keeps my life running, I enjoy a good show, and I’m all for using screens strategically. But understanding how light—especially blue light—affects your baby’s sleep means you can set some simple boundaries that protect those precious nighttime hours.

When you do, you’re not just helping your little one fall asleep faster—you’re helping them stay asleep longer and wake up happier. And that means the whole family gets the rest they need.

If bedtime battles, frequent night wakings, or the need for constant rocking are wearing you down, let’s chat.

📅 Schedule your complimentary sleep evaluation call and learn how we can create a sleep plan that works for your family—light management and independent sleep skills included.