What's really going on when a child is 'overtired'—and how to help them go to sleep

Anyone who's cared for a young child will recognize the signs. They've had too little sleep or missed a nap, they're cranky, tearful, and stroppy, and they can't or won't fall sleep. They are "overtired." But is such a thing really possible—to be more tired than tired?

What we tend to call overtiredness happens when an emotional state, such as anxiety, distress or fear, blocks our ability to go to sleep even when we're really tired. This is a survival response that helps us to stay awake when in danger, no matter how tired we are. It suggests overtiredness can be reframed to help us better respond to our child's needs when it happens.

At the end of the day, the feeling we have of needing to sleep is called sleep pressure. The longer we stay awake the more sleep pressure rises. Typically, the higher it gets, the easier it is to fall asleep. If we stay awake for long enough, eventually we'll fall asleep even if we are trying not to.

The sensation of sleep pressure is caused by the build-up of chemicals (called adenosines) in the brain. These are proteins that are removed from our brains while we sleep, and build up again while we are awake.

For adults, this process takes about 14-16 hours. When we delay sleep past this point the build-up of adenosines cannot go on unchecked. At some point, eventually, we must sleep.

Babies' sleep pressure builds up more quickly than adults. Young babies often fall asleep after being awake for an hour or two. As children get older, sleep pressure builds more slowly. But it takes several years until a child is able to stay awake all day.

What stops us sleeping?

To fall asleep we must be calm, relaxed and able to switch off our brains so that the build up of sleep pressure can tip us into sleep. When something blocks the action of sleep pressure, such as fear, pain or racing thoughts, we may struggle with sleeplessness.

In the same way, sleep happens more easily for a baby or child when sleep pressure is high, they are in a calm relaxed state, and nothing is preventing sleep onset. But sometimes babies and children need help to become calm before sleep pressure can kick in and they can nod off.

When a baby or young child's sleep pressure is high and the need to sleep is strong, but they are emotionally unable to calm themselves, or they are in a situation where they cannot relax—where there is noise, lights, or activity—we may label them as overtired. Emotional exhaustion, which is a form of stress, prevents both children and adults from sleeping and makes them cranky.

Some responses to overtiredness are heavy-handed. Ordering a child to their room, putting them to bed in the face of distress or punishing them for not falling asleep when told to do so will dial up the child further and push sleep further from reach. After all, none of us can fall asleep on command.

Helping babies to sleep

In this situation we must remember that babies and young children need our help to manage their emotions. It is our job as parents to help them become calm, dial down, and relax in preparation for sleep.

We can do this in many ways. Physical contact such as cuddling, rocking, stroking or patting works for most children, although it must be remembered that some neurodivergent children can find touch irritating rather than calming.

Non-contact methods also work. The presence of a relaxed slow breathing adult can calm a child, as can listening to gentle talking, singing and humming. In Czech, there is a specific word for lying with and helping a child to relax so they can fall asleep: uspávání.

There is no name in English for the process of helping a child relax so that sleep pressure can tip them into slumber, so we often don't discuss or acknowledge it. We can use it, though. And we can understand that what we have named "overtiredness" is the conflict between sleep pressure being high and something blocking the effect of that sleep pressure.

In this situation actively removing the blockage—fear, pain, anxiety—by helping babies and children to become calm is the quickest way to help them fall asleep.

Next time your baby is having a meltdown at bedtime, or your child is throwing a tantrum at the end of the day, hug them, cuddle them, talk gently to them and calm them. Let sleep pressure do its thing, and they'll be snoozing in no time.