What is sleep pressure and why is it so important for your baby's sleep?

Whether adult or baby, we have chemical messengers in our body and blood stream which make us feel sleepy. The amounts of these neurohormones gradually rise when we are awake, and drop off quickly when we are sleeping.

The longer that you are awake, the greater your need to sleep becomes and the easier it is to fall asleep. Stay awake for long enough and eventually you’ll fall asleep because of your high sleep pressure, even if you are trying hard not to!

This is such a simple concept really, and yet it holds the key to making your family’s sleep as easy as possible when you have a baby.

• Your baby’s sleep pressure rises much more quickly than yours. A toddler’s sleep pressure doesn’t rise as quickly as a baby’s, but may still rise more quickly than yours.

• Sleep pressure rises in variable ways, from baby to baby, and even from day to day.

• The drop in sleep pressure in the first few minutes of sleep can be quite sudden. Napping for just a few minutes can take the edge off the rising sleep pressure.

What gets in the way of easy sleep?

You know your baby. You might often get the feeling that your little child’s sleep pressure is rising quite high. But that doesn’t mean you need to put your little one down to sleep straight away!

If you think that your baby’s sleep pressure is high, and your baby is dialling up, you could simply experiment with your two baby-sleep superpowers to keep baby dialled down: a feed, or a richer sensory motor experience. Then when the sleep pressure is really high, sleep will look after itself.

When your baby is dialled up, it's much harder for the sleep pressure hormones to do their job. High levels of sympathetic nervous system activity interfere with easy sleep.

You might hear that sleep is controlled by sleep associations, but that misunderstands the sleep science. Sleep is under the control of the two sleep regulators, the body clock and sleep pressure. It’s high sleep pressure which sends babies (and all humans) to sleep. Sleep will happen wherever baby is and whatever you’re doing, once the sleep pressure is high enough. You don't need to be trying to build up sleep associations. We want to make your baby's sleep just as easy and no-fuss as possible!

Here's an illustration of what I mean by letting sleep pressure rise as high as possible. When I come in at the end of a long day, let’s say at seven o'clock in the evening, I feel very tired. I might start yawning. I could even snuggle down into bed and go to sleep right there and then. But I never do. This is because if I go to sleep early in the evening, and particularly if I start doing this as a pattern over time, I will find myself awake for long hours in the night, or waking at two o'clock or three o'clock in the morning and unable to go back to sleep. That is, I will start to have excessive night waking due to disrupted settings on my body clock. Instead, I wait for my sleep pressure to be really high, at say ten o'clock in the evening, before I go to bed. This is how I keep my sleep pressure in sync with my body clock, and how I keep both my sleep regulators in sync with sunrise and sunset and also with the sleep of other humans around me in my world.