Overtired vs. Undertired Babies (And What It Means for Their Sleep)

routines wake windows Oct 16, 2022

Did you know? Babies and toddlers experience different types of "tired" as they grow and develop. 

One type is overtiredness, which happens when they've been awake for too long and are (understandably) exhausted. This can make them cranky, fussy, and hard to put down for sleep. The other type is undertiredness, which occurs when they have had MORE sleep than they need and ironically can ALSO make them cranky, fussy, and hard to put down for sleep. (I know, great right?! Overtired and undertired can look SO similar!) 

But here’s the good news — by paying attention to your baby's behavior and adjusting their sleep and activity schedule accordingly, you can ensure they get the restful sleep they need.

With that said, it can be tricky to work out if you don't know the signs that I’ll share below. It can take some detective work sometimes!

So let us start with OVER tired. As that is probably the most common concern for parents, as it can cause a few challenges with sleep.


  • Awake times are much longer than the age average (you can learn more about awake times here).

  • Hysterical crying when you know there is nothing wrong

  • Rigid and stiffness in the body

  • Many night wakings

  • Many wakings in the first part of the night (before 2 AM)

  • Cranky during the day

  • Fights sleep due to increased cortisol from being over tired

  • Often gets "second wind" of energy when it's time to sleep

  • Hyperactivity

  • Crying and fussy in the morning when they wake up

  • Still seems tired and frustrated in the morning or after nap

If this sounds like your baby, click here to read how to get out of the overtired cycle!

There are usually two manifestations of an under tired baby or toddler:

  1. A baby or toddler who is happy, alert, ready to party!
  2. A baby/ toddler who is sleepy/easily goes to sleep if in the right environment but then seems to have sleep issues such as long night wakings etc.

Below I’ll share some typical signs for an under tired baby.


  • Sleeps a lot in the day

  • Baby seems to have lower sleep needs

  • Night wakings are happy and giggly

  • In a great mood all day!

  • Night wakings are later in the night (after 2 AM or so)

  • Takes super long naps

  • Split nights - when awake for 1-2 hours happily in the night

  • Goes down for nap but wakes up happy after 20-30 minutes

  • Refuses to go down for a nap and is totally smiling when you get them

  • Fights sleep (out of frustration, they aren’t tired yet).

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So there you have it: Overtired vs Under-tired.

It’s a tricky one, and it can take some time and learning and tuning into YOUR baby as an individual. Give yourself grace as you learn. Especially if you are a first time mum. It is hard enough everything else you are learning, so give yourself a break for not being able to figure this out right away. It takes time, and practice! Much like everything else in life. You are doing amazing ok!!! The fact that you are reading this at all shows me that. Don’t let anyone tell you any different!

Are you just constantly confused about your baby’s sleep? 

That’s where I come in! I’m really good at teaching you all about baby sleep.

The first thing you want to do is have a clear plan in place! If you’re really struggling & need support along with a step by step plan…I have got you covered!




If you need more help and you want someone to show you EXACTLY what to do, the Cozy Baby Sleep Course is a step-by-step program designed to teach you how to teach your baby to fall asleep on their own and sleep all night long. With personalized sleep plans, guidance on building a solid sleep foundation and creating a consistent sleep routine, the Cozy Baby Sleep Course can help you and your baby get the restful sleep you deserve. 


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