Why Does My Baby Wake Up at Night?

This is undoubtedly the most frequently asked question by all parents!

Is it due to a developmental milestone? A regression? Are they sleeping too much during the day or not enough? Perhaps they're simply hungry? Maybe they're too hot or too cold? Are they just bad sleepers?

The answer is that it could be one or a combination of those reasons...

Baby sleep is frustratingly complex.

Their bodies and brains are undergoing rapid and significant changes. Just when you think you've solved one issue, a new one arises to take its place. (Time to reach for that cup of coffee!)

There are certain factors you can control, of course. If the baby is cold, you can adjust the heating. If they're teething, medication can often provide temporary relief.

But those are simple short-term fixes. The reason why many parents struggle with their baby's sleep is because the problems aren't always straightforward and don't have obvious solutions.

Let's imagine a scenario: An 19-month-old child spends plenty of time outdoors, gets fresh air and sunlight during the day, and takes long and peaceful naps. However, when it's time for bedtime, they suddenly become full of energy and want to play. They get upset when told it's time to sleep, turning bedtime into a battle. Even when they eventually fall asleep, they wake up multiple times during the night and never sleep past 5:30 in the morning.

What's happening here? Could the baby be sleeping too much during the day?

That would be a reasonable assumption, one that most parents make. After all, if adults were to take a 3-hour nap in the afternoon, it's likely they would have trouble falling and staying asleep at night.

But the opposite is usually true. In this case, the baby is actually demonstrating a need for more sleep, not less.

To understand this counterintuitive reasoning, let's briefly delve into how the sleep system works. (Don't worry, I'll keep it concise and not bore you to sleep with too much science!)

About three hours before our natural waking time, our bodies start producing a hormone called cortisol. If you've read about your baby's sleep, the mention of this hormone might make you cringe a little. Allow me to explain...

Cortisol is a stimulating hormone and is also released during times of stress (such as facing threats in the case of evolution). In the morning, it helps us wake up and get started. Think of it as nature's caffeine.

If cortisol is our morning cup of coffee, melatonin is our evening glass of wine. As the sun sets, our bodies recognise the arrival of night and begin producing melatonin, a sleep-inducing hormone (which happens to be my absolute favorite, not just because I refer to it as the wine hormone). Melatonin helps us fall asleep and stay asleep until morning, when the cycle begins anew. Melatonin production increases and starts earlier in the evening when we're exposed to daylight.

However, as beautifully designed as this system is, it's not perfect and can easily become confused. So, in the aforementioned scenario, here's what's happening...

The baby takes great naps during the day, which is wonderful, and spends ample time outdoors, so their body is ready to produce melatonin at night. So why the sudden burst of energy right before bedtime?

When the baby's body starts producing melatonin, there's a narrow window of time when the body expects the baby to fall asleep. After all, she's a baby. What does she have to stay awake for? She isn't watching "The Real Housewives" or exploring the endless depths of TikTok (at least not yet).

The brain instinctively concludes that something isn't right, that for some reason, the baby can't sleep (imagine a bear attack). To enhance her chances of survival, the brain decides to release a shot of cortisol as a stimulant.

And that's exactly what happens. The baby's system starts secreting cortisol, and before you know it, she's a little wired. This often manifests as playfulness and an abundance of energy. In short, the baby missed the window for falling asleep, and now she's going to have a difficult time getting to sleep, even though her behavior doesn't suggest sleepiness.

So, what does all of this have to do with those dreaded 3 A.M. wake-ups?

Here's what happens... Assuming your baby's circadian rhythm is set for a 6 A.M. wake-up, her body starts producing cortisol three hours prior to that time. At this point, melatonin production for the night has ceased. Around 3:00 a.m., the baby reaches the end of a sleep cycle and enters a slightly awake state. At this point, there's a small amount of stimulant (cortisol) and no natural sedative (melatonin).

This, coupled with a lack of independent sleep skills, means the baby will likely wake up fully and struggle to fall back asleep.

Now, for the big question you've been hoping for an answer to: How do you fix it? While there's no quick fix for adjusting your baby's hormone production schedule, you can certainly help by ensuring she spends as much time outdoors during the day as possible. As mentioned earlier, natural light during the day is a major contributor to melatonin production at night (we really love melatonin).

It's also beneficial to make your baby's room as dark as possible at night and gradually dim the lights in the house at least an hour before bedtime. Mimicking the sunset helps cue the production of melatonin, so that it's in full swing when she goes into her cot.

Avoid any TV, iPhone, tablet, or screen time of any kind during that last hour before bedtime (preferably even longer), as these devices emit blue light (the nemesis of sleep) which stimulates cortisol production at a time when you're trying to avoid it. Above all, the most effective way to help your baby sleep through the night is to establish a predictable and consistent sleep schedule, and teach her the skills she needs to fall asleep independently.

Because the truth is, you can't prevent nighttime wake-ups entirely. We all wake up during the night, regardless of our age. As adults, we have the ability to calmly assess the situation when we wake up in the dark, realise where we are, see that it's still nighttime, and go right back to sleep. Most of the time, we don't even remember it the next morning.

So, while you can't prevent your baby from waking up at night, you can help her learn to recognise that she's safe, in a familiar environment, still tired, and capable of getting back to sleep on her own.

For more information on how to achieve this, you can download my guide "5 Tips to Get Your Baby Sleeping Through the Night."

I hope this blog hasn't put you to sleep, but if it has, maybe you could try reading it to your little darling instead... 😊