Overtired VS Under-tired
Overtired vs Under-tired Babies: What’s the Difference & How to Tell
It’s one of the most common reasons babies fight sleep; they’re either under-tired or overtired. And while the signs can look really similar, the solution is very different.
If your baby is having short naps, resisting bedtime, waking frequently overnight or rising early, there’s a good chance they’re sitting on the wrong side of their ideal wake window.
Let’s break it down.
What does it mean if a baby is overtired?
An overtired baby has stayed awake too long and missed their ideal sleep window. Once they pass this point, their body starts to release stress hormones like cortisol and adrenaline, which can make it even harder for them to settle and stay asleep.
Signs your baby might be overtired:
Fussing or crying when it’s time to nap
Arching their back or fighting feeds
Getting a “second wind” and seeming hyper
Waking 20–30 minutes into naps
Early rising or frequent overnight wakes
Taking ages to settle and then waking shortly after being put down
What about under-tired babies?
An under-tired baby hasn’t built up enough sleep pressure to be ready for sleep. This usually means they haven’t been awake long enough or haven’t had enough stimulation to help their body feel the need to rest.
Signs your baby might be undertired:
Happy or alert during wind-down or bedtime
Playing in the cot or taking a long time to fall asleep
Short naps but waking content and cheerful
Waking overnight but lying awake for long stretches
Resisting naps despite no signs of fussiness
But wait — the signs can overlap?!
Yep. Both overtired and under-tired babies can catnap or resist sleep. The difference often comes down to how your baby is acting.
A baby who is under-tired is usually still in a good mood, maybe babbling or playing in their cot. An overtired baby will often be cranky, unsettled, and harder to soothe.
How to fix it:
If they’re overtired:
Bring the nap or bedtime earlier
Watch for early tired signs (zoning out, turning away, losing interest in play)
Avoid pushing them to stretch longer than they’re ready for
Keep things calm and consistent. Overstimulation before bed makes it worse
If they’re under-tired:
Push the nap or bedtime later by 10–15 minutes
Add more stimulation- tummy time, fresh air, floor play
Check they’re not napping too much during the day
Make sure your wind-down routine is strong so they know sleep is coming
