Light, noise and activity tell your toddler's body clock that it's daytime, even when he's sleeping.

When your toddler falls asleep during the day, she is just taking the edge off her rising sleep pressure. We want her sleep pressure to be highest in the evenings, ready for the Big Sleep at night. She'll decrease her sleep pressure by a smaller amount, but enough, if she sleeps during the day in the midst of light and the sounds of life. Her body will take just what sleep she needs, but not more than she needs. Toddler sleep is always about patterns over time.

When your little one's sleep pressure is high enough, he'll go to sleep regardless of lots of noise and vigorous activity around him (as long as he's dialled down). He'll sleep through a rock concert if his sleep pressure is high enough.

Being put into a night-like situation during the day, such as into a quiet dim room, confuses your little one's body clock. A night-like situation tells the body clock to go into night-time sleep. This is why a quiet or darkened room tends to lengthen the amount of time she sleeps during the day. In sleep training approaches, parents might be advised to purchase blockout blinds for the toddler's bedroom!

But there is a big problem with this. If long daytime naps become a pattern, your toddler may develop excessive night-waking a few weeks down the track. The quiet dim room seems to help on the day, but often makes toddler sleep worse over time. You can find out more here.