Understanding the science of sleep can make it easier to support your little one’s rest. Babies sleep very differently to adults, and by learning what’s happening in their bodies, we can set them up for the best possible sleep.
Our bodies naturally follow a 24-hour cycle called the circadian rhythm. This rhythm tells us when it’s time to be awake and when it’s time to rest, based largely on light and darkness.
For babies, this rhythm isn’t fully developed at birth. That’s why newborns often mix up day and night. By around 3–4 months, their circadian rhythm begins to mature, helping them sleep longer stretches at night.
Melatonin – The Sleep Hormone
Melatonin is often called the “sleepy hormone.” It rises in the evening as it gets dark, helping the body prepare for rest. In babies, melatonin production is very low at birth but increases from around 8–12 weeks old. That’s one reason why consistent bedtime routines and dim lighting in the evenings can make such a big difference for your little one’s sleep.
Sleep Pressure – The Build-Up of Tiredness
Another key part of sleep is sleep pressure. Throughout the day, a chemical called adenosine builds up in the brain, creating the urge to sleep. The longer your baby is awake, the higher their sleep pressure becomes. Striking the right balance between enough awake time (to build sleep pressure) and not too much (to avoid overtiredness) is the secret to smoother naps and bedtime.
REM Sleep – Active Little Dreamers
During REM (Rapid Eye Movement) sleep, adults are usually paralysed to stop them from acting out their dreams. Babies, however, don’t yet have this safety switch fully developed. That’s why you might notice your baby twitching, smiling, sucking, or even wriggling in their sleep. This active sleep is perfectly normal and plays a big role in their brain development and processing of new skills.
The Effects of Poor Sleep on Babies
Sleep isn’t just about rest – it’s critical for growth, development, and wellbeing. When babies consistently miss out on quality sleep, it can affect them in several ways:
Mood and behaviour – poor sleep can make babies more irritable, clingy, or harder to settle.
Learning and memory – sleep is when the brain processes new skills and information. Ongoing sleep struggles can make it harder for babies to learn and retain what they experience during the day.
Physical development – growth hormone is released during deep sleep. Without enough of it, growth and healing can be impacted.
Immune system – quality sleep helps strengthen immunity, meaning overtired babies may become more prone to getting sick.
✨ When you understand these building blocks of sleep, it becomes clearer why routines, environment, and timing matter so much. Supporting your baby’s natural rhythms and needs helps everyone in the family get more rest.
Ready to Make Sleep Easier?
You don’t have to figure it all out on your own. At Littlefoot Sleep, I take the science of sleep and turn it into a personalised plan that works for your baby and your family. With the right support, you can see results in as little as seven days – more rest, fewer wakes, and a happier, well-rested household.
Let’s chat about it. Book your free 15 minute consultation today!
