If there’s one thing we know about tiny tots, it’s that they definitely don’t do lie-ins. Unfortunately some little ones can become pros at waking up before the sun has even risen – much to the horror of their zombified parents.

But what actually constitutes as “too early” when it comes to kids waking up? Dani McFadden, an infant sleep expert from The Daddy Sleep Consultant, says she’d define it as “anything less than 11 hours after going to sleep”.

“In our experience, babies can typically sleep 11-12 hours at night and so we always aim for 11 hours from waking time when working with clients,” she tells HuffPost UK.

On rare occasions, some toddlers can get away with sleeping only 10.5 hours at night and are still absolutely happy and content with that amount, she adds.

Lauren Peacock, a sleep consultant at Little Sleep Stars, defines early rising as a little one consistently being awake for the day before 6am.

Most kids are natural ‘larks’, she adds, meaning they typically wake up fairly early – between 6 and 7am is standard. “If it’s earlier than that, there are usually steps a family can take to push the wake-up time to at least 6am,” she says.

“In our experience, we usually see early wakings being driven by overtiredness, usually because of a lack of daytime sleep,” says Dani McFadden.

Lack of daytime sleep – or a wake window between the final nap and bedtime which is too long – will lead to a baby becoming overtired, she explains.

“This will usually increase the levels of cortisol in the baby and cortisol is what keeps us awake each day. Therefore, if there is an increased level of cortisol in the body (more than what would usually be produced) this can lead to a baby waking more frequently in the night or waking earlier in the morning.”

To sleep soundly until 6am or later, a child needs to be going to bed with enough sleep pressure (aka the physical drive to sleep) to do that, says sleep consultant Lauren Peacock. But sometimes they don’t build up enough of this sleep pressure in the day.

Things that can leave a little one low on sleep pressure are:

• too much daytime sleep
• insufficient awake time before bedtime
• a bedtime that is too early for them

Interestingly – and annoyingly for parents impacted – without enough sleep pressure, a child may actually still fall asleep well at bedtime, as all the behavioural cues suggest it’s time to sleep. But the problem often comes at the other end of the night, says the sleep expert, when staying asleep without any remaining sleep pressure becomes “fairly impossible”.

What makes life even trickier is if you then cut down the amount of daytime sleep your child has too much, or you keep them awake for stretches that are too long, or you send them to bed later in the hope they sleep later, this can also backfire and cause early-waking. It’s about getting a happy medium.

“This happens because when a child gets too tired, they release additional wakeful hormones which can interfere with the body clock and in turn make 5am feel like the right time to be starting the day,” explains Peacock.

“So even though a child might still have enough sleep pressure to carry on sleeping, their body clock insists that they should be starting the day.”

As a result, she says, it’s often the timing and/or duration of their nap and/or the time a child is going to bed that is driving the early start.

What probably won’t be music to parents’ ears after reading all of the above is that there are also some environmental factors that can wreak havoc on young children’s awake times.

Is your child hungry? Do they need a nappy change? Is there light creeping into the room? An increase in noise levels? Or a drop in temperature? These can all signal to your child that it’s time to get up and start the day. Cue: them standing in their cot, eyes wide open, shrieking at you; and you looking at your alarm clock and groaning hard.

If your child is waking up at the crack of dawn then there are (thankfully) lots of things you can do to try and address it.

The first thing you can do is check how much sleep your child is getting overall in a 24-hour period, compared to the evidence-based range.

The Sleep Foundation is a great resource for information around average sleep needs by age, says Peacock. If a little one is towards the bottom of the range, or below it, parents should try encouraging more daytime sleep (longer naps) and/or an earlier bedtime, she suggests.

And if this doesn’t work, then it’s a “good indicator” that overtiredness is the culprit, “in which case, continuing to top up a child’s sleep tank should eventually start to chip away at the early start.”

If an early-riser is getting quite a lot of sleep for their age, or if more daytime sleep worsens the early start, then Peacock recommends going the other way and gently cutting the daytime sleep a little shorter or trying a later bedtime.

“Whenever a child’s routine changes, parents need to be prepared to stick with the new timings for a week or so, before evaluating the impact, as it typically takes a good few days for a child’s body clock to begin responding,” she adds.

“It’s all about getting a child’s sleep pressure back into alignment with their body clock – not least because young children are driven much more by what time it feels like than what time it actually is. The trick is to stop 5am feeling like the right time to get up.”

In terms of making the environment more conducive to a longer sleep, McFadden says it’s “imperative” that the room remains blackout dark in the mornings as light can stimulate our little ones, just as their body is preparing for wake-up and sleep is naturally lighter.

“Also, it’s important for parents to be mindful of external noise starting at this time which can wake babies, for example: birds tweeting, traffic picking up on the roads and parents getting up for work,” she says. “This is where white noise, which plays all night, can be very helpful for blocking out that external noise.”

Sometimes parents do land themselves with a natural early bird and if that’s the case, and your kid is raring to go at 6am every day, then it’s often easier for parents to adapt their own routine rather than their child’s, says Peacock.

“If caregivers can edge the time they head to bed earlier by 15 minutes every three to five days, they can typically get to a place whereby starting the day a little earlier than they did pre-children feels a lot more humane.”