The moment a child drifts off, both body and brain shift into a more active mode.
of growth hormone is released
during deep sleep
shortens how long it takes to fall asleep — and cuts down night wakings.
around month three or four, when the body starts releasing melatonin at the right times of day. That's why the first weeks feel so unpredictable.
of a baby's sleep is in REM
(in adults it's only ~20%)
Their brain is working hard to make sense of everything around them.
Growth hormone drives bone development, builds muscle and repairs tissue. When sleep is disrupted, so is its release.
Overnight, the brain consolidates the day's experiences into long-term memory and strengthens the neural pathways that underpin attention and self-regulation.
The immune system recovers and keeps inflammation in check, while REM sleep gives the brain space to process the day's emotions — particularly important for young children.
Sleep-deprived children rarely appear sleepy. They tend to ramp up — wired, irritable, tearful and harder to settle. What reads as stubbornness is, more often than not, simply insufficient sleep.
A two-year NIH study identified measurable brain differences in children sleeping below the recommended hours — and two years on, those differences had not narrowed.
Ongoing sleep loss disrupts ghrelin and leptin — the hormones that regulate hunger and fullness — and raises the risk of weight gain and elevated blood pressure.
When sleep falls short, the immune system responds less effectively to infection. That's why children with inconsistent sleep get sick more frequently — especially in the early years, when immunity is still developing.