What is the role of sleep in a baby’s development?
Dr. Valleteau de Moulliac,
Consulting pediatrician for Laboratoires Sarbec
Sleep is an essential element in a child's development. When a child sleeps, they are not just resting—it's much more complex:
- They recover, which allows them to wake up refreshed (and us too!).
- They grow: it is mainly during sleep that growth hormone is secreted.
- Their nervous system and brain development are organized and refined.
- They memorize everything they have experienced, experimented with, or learned during the day.
- They dream, which especially helps them release the tensions accumulated throughout the day.
- Their immune system is strengthened.
But what about the baby?
From birth to two months, babies sleep about 16 to 20 hours a day, with few periods of active wakefulness. They go through phases of active sleep, which ensures brain maturation, and quiet sleep, which is essential for growth and proper physical development. The cycles last about 50 minutes and there are 16 to 20 per 24 hours, but they can follow one another without the baby waking up. That’s why your baby only wakes up about every 3-4 hours.
- Active sleep lasts from 15 to 25 minutes; during this phase your baby falls asleep and then sleeps deeply, but continues to move. They may make facial expressions, smile, blink, and move their hands. This phase allows for the establishment and development of neural circuits, and thus contributes to brain maturation. Then it evolves and represents only 30% of total sleep. Gradually, it will become the adult’s REM sleep, which corresponds to dream sleep.
- During quiet sleep, your newborn sleeps, appears calmer, and breathes with a regular rhythm. This period allows for recovery from physical fatigue. It is during this phase, among others, that many hormones are secreted, including growth hormone, which promotes the repair of tissues and cells. This phase then evolves into slow-wave sleep.
After the age of 2 months, baby’s sleep is made up of three stages: REM sleep, light sleep, and deep slow-wave sleep.
At 9 months old, the characteristics of sleep cycles become almost identical to those of adults: a total duration of 90 minutes and a sequence of 5 phases.
Your role in establishing, organizing, and respecting this sleep is fundamental, but that’s another story.
