Why the fear of overtiredness is causing short naps and early mornings
If you've spent any amount of time in the online baby sleep world, you've probably been warned about overtiredness.
“Don't let your baby get overtired."
"If you miss the sleep window, they'll be awake all night."
"If your baby gets overtiredness, it will be impossible to get them to sleep."
And while there is some truth to overtiredness, I often see parents become so worried about preventing it that they accidentally create a different problem altogether:
Short naps, early mornings, and a baby who simply isn't tired enough to sleep well.
Adjusting wake windows is not the solution to every sleep problem because not every sleep problem is related to imbalanced sleep pressure.
So let's talk about what overtiredness actually is, how it differs from undertiredness, and why the fear of it can sometimes work against good sleep.
What is overtiredness?
Overtiredness simply means your baby has been awake for longer than their body can comfortably handle.
Sleep pressure builds while your baby is awake and acts as the biological drive for nap and nighttime sleep. If a baby stays awake beyond their ideal window, the body begins releasing hormones like cortisol to help them stay alert.
This stress response can make it harder for babies to settle to sleep and can interfere with the quality of their sleep once they finally do fall asleep.
What does being overtired look like?
Every child responds differently to being overtired, but generally there are some common signs and symptoms across the board.
Some babies struggle to fall asleep entirely. They seem exhausted but keep popping awake just as they're about to drift off. Others might fall asleep fairly easily but wake up frequently through the night, or start their day earlier than usual.
Common signs of overtiredness include:
Fighting naps or bedtime
Short naps
Waking up cranky from naps
Increased night wakings
Early morning waking
Crying out during sleep
Irritability during wake windows
Hyperactivity or seeming "wired"
High-pitched crying
Frequent yawning
Emotional meltdowns
The tricky part: undertired and overtired can look similar.
And this is where many families get stuck.
An undertired baby might:
Fight sleep
Take short naps
Wake during the night
Wake early in the morning
And an overtired baby might do the exact same things.
Super helpful, right?
There isn't a universal list of signs that tells you exactly which one you're dealing with, but following an age-appropriate schedule and then observing your child's patterns over several days, you'll get a better sense of what's going on.
Top tip: If you’re conscious about timing or constantly tweaking the schedule then blaming yourself if you’re ten minutes off, your baby’s sleep problem is likely not rooted in a sleep pressure issue and you might want to explore sleep training options. On the flip side, if you’ve never considered timing of sleep, adjusting wake windows may be helpful!
For example, some babies have lower sleep needs than others, and their protests at nap time or bedtime might be confused with overtiredness when they’re actually undertired.
This is why I never make sleep decisions based on one difficult nap or one rough night. Patterns matter matter way more than one *off* day.
How do I know if my baby is undertired?
Undertiredness happens when your baby simply hasn't built enough sleep pressure before sleep. Sleep pressure is your body's natural drive for sleep. It builds during wake time and helps your child fall asleep and stay asleep. The longer you're awake, the stronger it becomes.
When babies nap too frequently, spend too much time sleeping during the day, or are put down before they're tired enough, they may not have sufficient sleep pressure to take a long, restorative nap.
Signs of undertiredness can include:
Taking a long time to fall asleep
Playing or rolling around in the crib
Consistently short naps
Split nights
Early morning waking
Resisting bedtime
In many cases, parents become so worried about overtiredness that they shorten wake windows, unintentionally preventing sleep pressure from appropriately building.
Are my baby’s short naps being caused by undertiredness or overtiredness?
If your baby is under 5 months old, short naps are completely normal. A 20-, 30-, or 40-minute nap can be developmentally appropriate because your baby's sleep cycles are still maturing.
Yes, we can optimize timing, routines, feeding, and the sleep environment, but some of it is simply development. Oftentimes, younger infants just need a bit of help with daytime rhythms until naps are better established around 5 months.
Once your baby is 5 months or older, the short naps are worth investigating. At this age, most babies are capable of linking sleep cycles and taking longer naps.
If short naps persist, possible causes include:
Inconsistent timing of sleep
Dependent sleep associations
Overtiredness
Undertiredness
Time to drop a nap
So how does undertiredness cause short naps?
This is one of the most common patterns I see. After a baby takes a short nap, parents understandably assume:
"They must be tired from that “poor nap”. Let's put them down earlier for the next nap."
The problem is that shorter wake windows often mean less sleep pressure, then the next nap is short too, and the cycle repeats.
A great example is a 5-month-old taking four short naps every day. Parents often continue offering that fourth nap because the first three naps are so short. In reality, many babies at this age need longer wake windows and a three-nap schedule to start getting those longer, restorative naps.
What seems like a good solution to avoid overtiredness isn’t actually the solution at all. Knowing when to drop a nap can be challenging, but in this case fewer naps and more sleep pressure might be the real solution.
Are my baby’s early mornings being caused by undertiredness or overtiredness?
Sleep is governed by two things: sleep pressure & the circadian rhythm
Either of these becoming misaligned can be a reason why early mornings are happening.
Common causes of early mornings include:
Too much daytime sleep
Not enough wake time throughout the day
Bedtime that's too early
An age-inappropriate nap schedule
A nap transition that needs to happen
Overtiredness
So how does undertiredness cause early mornings?
If your baby wakes at 5:30 AM and immediately starts their day, it's tempting to move everything earlier– earlier first nap, earlier second nap, and earlier bedtime. Similarly to the short nap cycle, parents might think that their baby needs an early nap because “they must be exhausted from waking up too early!”
The issue is that this can reinforce the early waking pattern because your baby's internal clock is now set earlier and expects sleep and wake times earlier and earlier.
Keeping the first nap anchored to its usual time, even after an early wake, helps prevent the schedule from drifting earlier.
When does an early bedtime help the sleep schedule?
Now before everyone panics and throws out their early bedtime, early bedtimes absolutely have their place.
An early bedtime can be incredibly helpful when:
A nap was missed
Your baby is genuinely tired
You're navigating a nap transition
Your child is sick
Travel has disrupted sleep
The key is understanding that an early bedtime is typically a short-term tool, not a permanent solution for every sleep challenge.
Using an early bedtime strategically can help your child catch up on sleep, but using it every day for weeks may accidentally contribute to early rising.
Here's what you should know about overtiredness:
It is absolutely real, but it's also not the catastrophe the internet sometimes makes it out to be.
Every baby and toddler gets overtired. That’s just part of having a full life!
The goal isn't preventing overtiredness at all costs but understanding your child's sleep needs at large. Don’t let the fear of overtiredness keep you chained to an unsustainable sleep schedule!
Good sleep is not a goldilocks situation.
If you want more guidance in understanding your baby’s sleep needs, you can grab my most requested sleep resources (including sample sleep schedules!) for free.
Always cheering you on.
To better sleep,
Ella