Why Won’t My Baby Nap During the Day? Darkness Helps

If your baby is fighting naps during the day, you’re not alone. “Why won’t my baby sleep during the day?” and “how do I get my baby to stop fighting naps?” are some of the most Googled parenting questions out there - and for good reason. Daytime sleep can feel like a mystery to new parents: one minute your baby’s rubbing their eyes and yawning, the next they’re overtired, cranky, and wide awake.

At Porta Fox, we understand just how challenging naps can be, especially when your little one seems to resist them with every fibre of their being. That’s why we’re digging into the science behind daytime sleep and exploring one factor that’s often overlooked but hugely impactful: darkness.

There’s a growing body of research and decades of sleep consultant experience showing that a dark sleep environment helps babies nap longer, settle faster, and regulate their internal body clocks. In this article, we’ll unpack why darkness matters, how it affects baby brain development, and what you can do if your little one fights sleep during the day.

Daytime Naps Aren’t Just a Bonus, they’re Crucial for Brain Development

It might feel like naps are just a break between feeds or an opportunity for you to grab a shower, but they’re actually doing serious behind-the-scenes work. Researchers have found that naps are essential for babies’ memory consolidation and brain development. According to Professor Rebecca Spencer, a neuroscientist at the University of Massachusetts Amherst, naps give an immature hippocampus (the brain’s memory centre) the downtime it needs to process and store new experiences1. In a study published by the University of Colorado Boulder, infants who napped shortly after learning were more likely to retain that information later, indicating that sleep plays a direct role in supporting learning and cognitive growth2.

In other words, when your baby naps, they’re not just resting - they’re learning.

Darkness Triggers Melatonin (Even During the Day)

So why does a dark room help? Darkness signals the body to release melatonin, the sleep hormone that helps regulate circadian rhythms. While melatonin production naturally ramps up in the evening, research shows that exposure to bright light, even during the day, can suppress it and make it harder for babies to settle3.

Dr Jay Lovenheim, a pediatric sleep specialist, explains:

“Complete darkness is beneficial for newborns up to four months old because it helps establish their sleep patterns and eliminates overstimulating visual input”4.

Fighting Daytime Naps? Here’s Why Darkness Helps

If your baby resists naps during the day, you’re likely dealing with overtiredness, overstimulation, or a mismatch in sleep cues. One of the most common mistakes is trying to get a baby to nap in a bright or stimulating environment. Light, noise, and movement all signal “it’s playtime”, and babies, especially after 3 to 4 months, are very responsive to those cues.

That’s where darkness works like a reset button.

Creating a consistent, dark sleep space helps your baby recognise when it’s time to wind down. It removes the visual stimulation that can keep them wired (like ceiling fans, shadows, toys, or movement outside the window) and tells their brain: it’s safe to switch off.

For this reason, many sleep consultants recommend using blackout blinds for both naps and overnight sleep, especially when you’re trying to create a consistent routine.

But Won’t Blackout Blinds Make the Room Too Hot?

This is a question we hear all the time, and it’s a valid one. Many parents worry that making a room pitch black will also trap heat, especially during warmer months or in sun-exposed nurseries.

The key is choosing the right kind of blackout blind. Porta Fox blinds are made from a multi-layered fabric that has a silver backing that not only blocks light but also reflects heat, helping keep the room cooler on hot days. This is especially important for babies, who are more sensitive to overheating.

A good blackout blind should balance light-blocking power with thermal protection, something we’ve designed into every detail of our product.

Are Babies Meant to Nap in the Dark?

There’s some debate here. While many sleep experts advocate for dark nap environments, some, like Professor Helen Ball at Durham University, suggest that daytime naps with natural light and background noise might better reflect real-world conditions, especially for newborns5.

Every baby is different, and not every home setup allows for a fully dark room. But what’s important is consistency. Whether you aim for full blackout or simply a dimmed environment, the goal is to create a clear and repeatable signal that it’s time for sleep.

If your baby is still struggling to nap, try combining a darkened room with a predictable wind-down routine like a feed, cuddles, a story and white noise. Often it’s not the nap they’re fighting, but the transition from activity to rest.

Takeaway: Darkness Isn’t a Sleep Trick, It’s a Biological Cue

If your baby struggles to nap, don’t assume they’re just “not a good daytime sleeper.” Often, it’s their environment doing the heavy lifting (or working against you). And one of the simplest, yet powerful, tweaks you can make is controlling the light.

A dark room helps regulate melatonin, reduce stimulation, and encourage restorative daytime sleep. Combine a repetitive pre-nap routine and a high-quality blackout blind that won’t overheat the room, and you’re giving your baby every chance to rest, recharge, and grow.

References

1. Spencer, R. (2023). University of Massachusetts Amherst Study on Infant Memory and Sleep. Retrieved from umass.edu

2. Horger, M. N. et al. (2019). Sleep-dependent memory consolidation in infants: Increased retention across naps. Developmental Science, 22(2), e12763. University of Colorado Boulder Study

3. Figueiro, M. G. et al. (2002). Light suppresses melatonin production in children and adolescents. Journal of Clinical Endocrinology & Metabolism, 87(7), 3164–3169. 

4. Dr. Jay Lovenheim quoted in “Should Babies Nap in the Dark?” (2023), amumtomum.com

5. Ball, H. (2025). “Put your baby down to nap near a washing machine,” The Guardian. Retrieved from theguardian.com