How melatonin affects sleep

Melatonin is often referred to as the sleep hormone which is associated with the onset of sleep.

Melatonin is produced by the pineal gland portion of our brains which is influenced by the body’s internal clock. The release of melatonin is in sync with our body’s circadian rhythm, which means that’s its cycles of high and low levels repeat themselves every 24 hour. That is why we generally feel sleepy at the same times each day.

When a baby is born it doesn’t have a developed body clock. That takes around 3-4 months to be fully developed. This is also the time when a baby’s brain starts producing melatonin which puts their sleep cycles into a more regular rhythm. If a baby was born prematurely, he might not start this process until a couple of months later, depending on how early she was born. Babies are born with some maternal melatonin which they get through the placenta, however by 8 weeks it has come out of their system. That can explain the new born sleepiness.

Melatonin levels in the body are also very much affected by light. The pineal gland that releases melatonin takes in information about light through the eyes and production of melatonin is dependent on the amount of light registered by the eyes. That means it increases melatonin levels when it’s dark and suppresses them when it’s bright. The highest levels of melatonin are therefor released at night. Melatonin raises in the evening and continues to raise until about midnight. And because we are pumped full of those nice sleep hormones, the period between bedtime and midnight is often perceived as the most restorative sleep.

Around midnight melatonin levels drop, which could explain why many babies sleep well until then and after midnight wake frequently.
By 5am melatonin has gone from our system, and we enter the period of light sleep. So if anything is bothering the baby, like hunger, being cold, light, noise etc, they will struggle to get back to sleep.

Exposure to artificial light, especially from screens, will suppress the release of melatonin in the brain, which will cause wakefulness.
The eyes of babies and kids are more sensitive to light than the eyes of adults, which means their melatonin levels are more strongly affected by light exposure.

One study showed that children exposed to a bright light before bed had a 90% reduction in their melatonin levels compared to a different night at the same time without bright light exposure. And most children were still at only 50% of their normal melatonin levels an hour after the initial light exposure.

New born babies who aren’t exposed to any artificial light develop circadian rhythms for melatonin release earlier than those who are exposed to artificial light, and as a result develop a circadian rhythm for sleep earlier.

Here is what you can do to help your child more of that good sleep hormone:

* Limit your child’s exposure to artificial light, especially near their bedtime.
* Dim the lights in the house before bedtime. A bright lit room will cause melatonin suppression and consequently struggle to fall asleep.
* Limit light exposure when your baby or child wakes up in the night. When you’re feeding your baby at night, only use a very dim light if you need to.

As you can see, the connection between melatonin, light and sleep is extremely strong so being mindful of your child’s light exposure and their sleep needs will go a long way towards improving their sleep.