Why keeping your toddler’s sympathetic nervous system more or less dialled down helps with easy, no-fuss sleep

A dialled up sympathetic nervous system gets in the way of easy baby sleep

There are two fundamental biological drives which dial up your toddler's sympathetic nervous system. These are your toddler's

• Hunger and thirst, and

• Hunger for richer sensory motor experience (which could be contact with your or another loving adult’s body, or a change in sensory environment).

A dialled up sympathetic nervous system makes it more difficult for one of your toddler's sleep regulators, the rising sleep pressure, to do its work of switching on sleep. You can find out about your toddler's sleep regulators, the body clock and sleep pressure, here and here.

When you use your two toddler-sleep superpowers to dial your small child down, her sleep regulators do their job of sending her to sleep easily. This is why knowing how to use these superpowers is vital for enjoyable and easy sleep in your family. Your toddler-sleep superpowers are

1. Flexible breastfeeds, if your toddler is breastfeeding. How and when you use milk, if your toddler is not breastfeeding depends on

   • The age of your toddler

   • Whether or not you are still using the bottle. You can find out more toddlers, milk and sleep here, here, and here.

2. Rich and changing sensory motor experience.

Why does a dialled up sympathetic nervous system interfere with sleep?

I often use an example to show how this works physiologically for myself as an adult. Let's say I go to bed at night knowing I need to give a big presentation the next day. When I feel stressed, I can find it difficult to go to sleep. My sympathetic nervous system dials up even more as I lie there, imagining the next day. My body might feel tense and my mind becomes busy. These high levels of sympathetic nervous system activity override the neurohormones of my building sleep pressure. I can't go to sleep.

This is what happens in toddlers who are dialling up. Eventually your toddler's sleep pressure might kick in anyway after a period of crying, and your little one goes to sleep, but it could all have been so much easier!

Recommended resource

How to nurture the flourishing of your baby's or toddler's brain

I recommend the program Tuning into Toddlers Online (TOTOL), by Professor Sophie Havighurst and her team at Mindful, The University of Melbourne, Australia. TOTOL helps parents shape their toddler's behaviours in a way that keeps emotional connection strong. You can access TOTOL here.

Selected references

Gottman JM, Katz IF, Hooven C. Parental meta-emotion philosophy and the emotional life of families: theoretical models and preliminary data. Journal of Family Psychology. 1996;10:243-268.

Havighurst SS, Kehoe CE, Harley AE. Tuning in to Toddlers: Research protocol and recruitment for evaluation of an emotion socialization program for parents of toddlers. Frontiers in Psychology. 2019;10(1054):doi: 10.3389/fpsyg.2019.01054.

Havighurst SS, Kehoe CE, Harley AE, Thomas R. A randomized controlled trial of an emotion socialization parenting program and its impact on parenting, children’s behavior and parent and child stress cortisol: Tuning in to Toddlers. Behavior Research and Therapy. 2022;149:104016.

Johnson AM, Hawes DJ, Eisenberg N. Emotion socialization and child conduct problems: a comprehensive review and meta-analysis. Clinical Psychology Review. 2017;54:65-80.