In our work with mums and dads whose babies just want to party all night long, very often the only thing “wrong” is either that their baby has had too much day sleep or hasn’t had enough! Undertiredness and overtiredness are the biggest contributors to poor napping. It’s actually all rather scientific:
Babies need a delicate balance of day sleep vs night sleep – too LITTLE day sleep results in cortisol (a stress hormone) building up in your baby which will make them harder to settle and also lead to night waking or early morning waking. Cortisol triggers the “fight or flight” function in babies and is like adrenaline coursing through their bodies…Impossible to sleep well under those conditions! Equally too MUCH day sleep can also lead to a lot of night waking and your baby being unsettled overnight because they just need some awake time.
To put it simply, we need to look at the whole 24 hour period. Babies have a specific amount of sleep hours they can do in 24 hours, based on their age. If your baby is doing a lot of these sleep hours during the day, of course they will sleep less at night. The goal is to find the right balance.
And the balance is constantly changing as your baby gets older. It is governed by two things: awake times and nap lengths.
This is the chunk of time your baby is awake for between each sleep (including feeds). If a baby’s awake times are a little too short between naps they won’t be tired enough to nap properly at the right times – this can mean they struggle to fall asleep for naps and at bedtime (because they’re not tired enough), and, if they do fall asleep, they’ll only sleep for a short time. Something we see very regularly is parents seeking our assistance because they can’t get their baby to fall asleep, assuming their baby is OVER tired, when actually their baby is UNDER tired.
I know how they feel.
With my second baby, knowing very little about awake times, but determined to stop him getting overtired, I was trying to put him to bed too soon for his naps every time and then wondering why he just wasn’t falling asleep. I remember getting so frustrated, upset, stressed out, convinced there was something wrong with my baby. In hindsight, he just wasn’t tired enough to go to sleep yet. Once I cottoned on to the magic of the RIGHT awake time, we were away laughing. The important thing to remember is that awake times change very quickly (especially with young babies). A brand new baby can only stay awake for around an hour at a time, yet by 3 months old this awake time has stretched to 2 hours. Many people fall into the trap of not increasing their baby’s awake times as they get older, then, like me, wonder why their baby suddenly isn’t going to sleep as easily as they did before. A baby who is good and ready for sleep at the right time should fall asleep very easily. (See THIS video for how to settle your baby to sleep under 3 months old).
The opposite of undertiredness is overtiredness; keeping your baby up for too long between naps will mean they are just as hard to settle. Remember the cortisol hormone from earlier? It rears it’s ugly head if a baby is really overtired, which, completely unjustly, means your baby will then sleep worse as a result of their overtiredness. Waking after 45 minutes at bedtime, frequent night waking or early morning waking can be directly linked to a buildup of “sleep debt” during the day due to too much awake time and not enough nap hours. Which brings us to:
Once you’ve got awake times sorted, you need to look at the second part of the equation, nap lengths, and check that your baby is having the right amount of nap hours to lead to a well-rested baby who wants to sleep well at night. Here is a guide to help you (allowing for 12 hours overnight):
|Age||Daytime cumulative nap hours|
|2-3 weeks||5 ½ hours across 3 sleeps|
|3-5 weeks||5 hours across 3 sleeps|
|5-7 weeks||4 ½ hours across 3 sleeps|
|7-9 weeks||4 hours across 3 sleeps|
|9-12 weeks||3 ½ hours across 3 sleeps|
|3-4 months||3 ¼ hours across 3 sleeps|
|4-6 months||3 hours across 3 sleeps|
|6-9 months||2.5 hours across 2 sleeps|
|9-12 months||2-2.5 hours across 2 sleeps|
|12-24 months||2 hours across 1 sleep|
As well as meeting the total allocation of nap hours, the way those hours are divvied up is just as important. It is physiologically better for babies and toddlers to get a good chunk of sleep in one consolidated nap around midday when all humans have a natural dip in their energy levels (from 12-2pm). A long nap at this time is most beneficial to your baby's 24-hour sleep log, so if a baby sleeps for too long in their morning nap and then doesn't have a long enough nap at midday, they will be going into the afternoon and then bedtime with a greater build up of sleep debt/overtiredness.
What we commonly see in babies over 3 or 4 months old is catnapping – sleeping for only one sleep cycle at a time. This is a developmental occurrence at this age (called the 4 month sleep regression) and while some of these babies will still be meeting their cumulative daily nap hours through several 45 minute naps, they don’t have the chance to catch-up on that restorative sleep and will still be in quite a lot of sleep debt come bedtime. If your baby is in this category, helping them learn to self-settle is your best line of defence against catnapping.
So to gel together awake time vs nap time, here comes the sometimes contentious part… WAKING THE BABY. While it might seem very counter-instinctive (or downright mean) to wake a sleeping baby, we do advise doing it if your baby is at risk of having had too many daytime sleep hours, or of sleeping for too long in the morning nap which will mean their lunch nap is consequently shorter, or if they're sleeping too late or long in the afternoon which will have a negative impact on their bedtime settling and night time sleep.
I always hold to the mantra “it is better for you to wake your baby in the day rather than your baby wake you in the night”. Some babies are better day sleepers than others. My youngest is like this. She would quite happily snooze the day away and then party all night. Because I have 2 older children and a pretty busy day-to-day life, I’m not okay with this! For me, being in control of her daytime sleep hours is really important to ensure she sleeps well at night.
Like I said, it’s a balance. And sometimes it is really tricky to get it right.