What controls the circadian rhythm in babies and when is it developed?

At 6 week old baby has no idea about day or night, and has no 24 hour rhythm. By 60 days, to 3 months (12 weeks) this rhythm is developed or developing.  Hormones are beginning to shape your baby’s day and night. This internal biological clock is controlled by a part of the brain called the hypothalamus – in a small section known as the SCN. The SCN receives information from the eyes, from temperature, social cues and food availability.

Natural dawn light is white/blue light which encourages us to wake up by cueing the release of Cortisol, the wake up hormone. As the day passes to night natural light becomes orange/red light, encouraging the brain’s release of Melatonin, the hormone of sleep. Using electric white/blue light when attending to your child at night, is stimulating the release of “wake up” hormone. Using a low level red/orange light is going to naturally be less disturbing,

If food is always available from 7pm to 7am, you are training your baby to regularly be awake at night expecting food.  Again, this disrupts the body clock. Few children, from 9 months old, physically require feeding at night. These late night milk feeds have other physiological effects on babies. When babies consume milk, their bodies produce insulin in response to this. Insulin secretion has actually been shown to block the production of melatonin the sleep hormone.

These lowered levels of melatonin are what then create a fitful night’s sleep for your baby, who then struggles to get into a nice deep sleep cycle without enough of this hormone. This is why, if you resisted that feed after midnight, your baby would eventually settle until morning – even if you heard them wake and re-settle a few times.

Night time feeding also delays the production of another hormone called ghrelin, this hormone helps control appetite. Studies show as the number of hours of sleep increase, ghrelin concentrations decreases, thereby reducing appetite. This reduced appetite allows your baby to sleep for longer period without waking hungry.

So not only are there hormones disrupting his sleep, an excessive fluid intake can cause him/her to wake up wet and uncomfortable, and the milk in the digestive tract is sending information to tiny little biological clock controls, to tell baby to wake up, as food available = day time!

Each time your baby sees your beautiful face at night contributes to disruption by sending messages to that SCN in the brain that this is a social time of day and not a time to be sleeping. This further confuses your baby’s circadian rhythm. This is the  truth behind the strict “no eye contact no smiles at night” that parents are encouraged to follow. Eye contact and using a name is encouraging the possibility of a prolonged interaction, play or negotiation. Night time is sleep time and this should not be negotiable.

If you would like help and support to alter your child's sleep behaviour;-
Contact us at  info@dream-angus.com