That's because overtired babies have a harder time settling down for sleep, sleep only intermittently and wake up more often throughout the night. ... Overtired babies tend to sleep less and sleep less well, making them more tired, which continues the tired-overtired cycle.

Why do babies sleep less when overtired?

Cortisol helps to regulate the body's sleep-wake cycle; adrenaline is the fight-or-flight agent. With these two hormones at elevated levels, expecting your baby to just settle down and go to sleep may not be realistic. In fact, if your baby is overtired, they may also find it hard to stay asleep.

What do you do when overtired baby won't sleep?

Try lots of reassurance : 1) Talk quietly and cuddle your baby until calm 2) Put your baby on their back in the cot awake (drowsy) 3) Comfort your baby with gentle 'ssshh' sounds, gentle rhythmic patting, rocking or stroking until baby is calm or asleep.