Short on time? Then the key things to know are:
- Split night sleeping is when your baby wakes in the night after a long sleep and stays alert for an extended period
- Babies waking due to split night sleeping tend to be fully alert, rested, and awake for one long stretch multiple nights a week
- Split nights occur because your baby hasn’t yet aligned their internal body clock with when they feel sleep pressure
- In some cases, babies learning new skills or being unwell can also result in middle-of-the-night wakings
- There are plenty of ways to fix split night sleeping such as reducing or lengthening day time naps, shifting bedtime earlier or later and ensuring they’re not overtired
- The right method for you depends on why your baby is waking in the night and how long they tend to nap for
Split night sleeping often occurs in infants under one and can be a very challenging time for both babies and parents. But by understanding why and making simple tweaks to their routine, you can regain a healthy sleep schedule.
Here we share some tips to help you manage your baby’s sleep.
What is split night sleeping?
Split night sleeping happens when your baby or toddler sleeps for a stretch of time at night but then wakes up a few hours later. They then can't fall back asleep for an extended period, with some babies happily staying awake for several hours.
The main difference between split nights and regular night time wakings is that babies will be awake for a few hours at a time, normally multiple nights a week, often happy and not wanting to settle. Babies may act playful and be fully alert, therefore unable to fall asleep because they are awake and rested.
The two processes that control how we sleep
Before we can learn how to manage your baby’s split night sleeping, first it’s helpful to understand the two separate processes that impact how our sleep is regulated. These are:
- The homeostatic sleep process, and
- The circadian rhythm with its 24-hour sleep-wake cycle.
The homeostatic sleep process Adenosine is a natural chemical that helps us get sleepy, known as sleep pressure. Adults and babies produce and get rid of adenosine in different ways, the key difference being that babies’ levels of adenosine increase whilst they are awake. This means they can only stay awake for a certain amount of time before they start to feel tired. This time is what’s commonly known as awake, or wake windows.
If we already have lots of adenosine, our body will slow down or pause making more. This happens whilst we sleep. Babies that are awake for a long time in the night therefore have less adenosine levels.
The circadian rhythm Next up is the circadian rhythm. This is a natural process that is controlled by our internal biological clock and is affected by how much light and dark we are exposed to. We start to develop a circadian rhythm at about eight weeks old however it’s not yet programmed to our 24/7 cycle.
At around three months, we start to produce melatonin which helps us to adapt to a day-night pattern of sleeping. Daytime naps will typically get shorter and babies should spend more time asleep at night. Both this circadian rhythm and the homeostatic sleep process will then start to work together in the evening, helping babies to feel sleepy and stay asleep.
However in the case of split nights, these two processes are misaligned, with sleep pressure continuing to build regardless of the circadian rhythm. That is why some babies will wake in the middle of the night and upon waking, be fully awake.
What causes split night sleeping?
Too much daytime sleep and too early bedtimes
Infants aged 4 to 12 months will on average sleep between a total of 12 - 16 hours within 24 hours, with the majority of sleep taking place in consolidated stretches at night. For newborn babies, this is anywhere between 14 to 17 hours, or even longer.
Some babies can easily nap past the 2-hour mark several times a day which will then interfere with night sleep, particularly if naps occur late in the afternoon. That is because your baby may not have built up enough sleep pressure if put down at their usual bedtime. After all, they have not been awake long enough since their last nap.
Too little daytime sleep and too early bedtimes
Another scenario where split nights can occur is when your baby struggles with their naps and does not sleep enough during the day. As a result, you may put them to bed earlier than their usual bedtime, and if the 'bad naps' consist, you may do so for the coming days with bedtime incrementally shifting forward.
Gradually your baby's sleep pressure will decrease (meaning they don’t feel the need to sleep) and will also misalign with their circadian rhythm, resulting in them waking fully in the night.
Bedtime is too late or they’re overtired
Say your baby has been awake for longer than comfortable and shows clear signs of overtiredness (reaching peak sleep pressure), yet they are still awake. In this case, their brain may trigger a stress response by releasing cortisol and adrenaline.
High levels of these hormones will begin lowering their sleep pressure levels, making it hard for your baby to settle and stay asleep.
New skills or illness
Sometimes split nights can also occur because your baby is making a leap in their development and is learning new skills. Often babies are even more susceptible to external stimuli and overstimulation during this time, or they are keen to practise their newly acquired skills in their cot.
Equally, illness resulting in physical discomfort can play a major part in babies waking in the middle of the night and ultimately disrupting their sleep.
What can you do to fix split night sleeping?
Shift bedtime back
The first step is to adjust your baby's bedtime. For example, if your baby is napping later in the day yet is still being put to sleep at their usual bedtime, try moving bedtime back by 15 to 30 minutes. Then wake them 15 to 30 minutes earlier in the morning. This is a temporary adjustment to help realign their sleep pressure and circadian rhythm.
Cap their naps
Some babies are ‘nap ninjas’; unphased by noise and able to sleep in any situation. However, we don't want them to oversleep. Try to wake them around the 2-hour mark and then keep them awake for their age-appropriate wake window.
Lengthen short naps
On the other hand, we have ‘cat nappers’, who sleep 30 minutes or less in one nap during the day. Try to lengthen their naps by making adjustments to their sleep environment such as darkening the room, offering sleep props like a comforter, and learning to soothe them towards the end of their sleep cycle.
Want to speak to someone about baby sleep? Book an appointment with one of our baby sleep consultants at a time that suits you to get specialist advice with any concerns.
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Miriam, Sleep Consultant
Miriam is a qualified Baby and Child Sleep Consultant who feels passionately about helping other mums experience the benefits of good sleep. Her approach is gentle, relationship-centred and research-informed.