Circadian Rhythm and Babies: Why Won’t My Newborn Sleep??

Apr 21, 2022

Ah, the circadian rhythm. One of those things that gets brought up a lot but rarely explained. The circadian rhythm is an essential part of everybody’s ability to sleep well, regardless of age or gender – heck, regardless of species!

The circadian rhythm is a standard biological feature in most animals and plants, and even some microbes. At its most basic, the circadian rhythm is how an organism’s body follows particular processes over 24 hours. The body’s circadian rhythm touches many aspects of everyday life, but it is most famous for wake and sleep windows. For example, most cows are awake during the day and sleep at night. Most owls are asleep during the day and awake at night. Some flowers and plants open up their leaves and flowers in the morning and tuck them away once the sun goes down.

And people – well, for the most part, people are awake during the day and asleep at night. This natural rhythm goes back to the early people who, with the absence of light-making technology, had only one option: work in daytime hours and sleep once the sun goes down. Over the next million years or so, the inventions of the candle, oil lamp, and electric lightbulb have allowed humans to stretch their workable daytime hours a bit, but for the most part, people still work when the sun is up and sleep within a few hours of darkness.

So why aren’t parents of newborns getting a full night’s sleep from day one?

Wouldn’t that be a treat! Even though the circadian rhythm is a biological system, it doesn’t kick in until a newborn has a few months of life under their onesie. Baby bodies don’t usually start producing the standard sleepiness and wakefulness hormones until they are between three and five months old.

That seems like a long time when you are sleep-deprived, but luckily, we have some baby sleep help ideas to “train” your newborn to sleep from day one. These tips are not *technically* sleep training, but they are five good habits that help your baby’s body regulate to a more consistent sleep schedule.

  1. Keep sleepy time dark: Remember how we talked about those prehistoric humans? Their nights were very dark. We’re talking, camping in a cave in the middle of Wyoming at midnight dark. So draw the curtains, put up window-darkening cling, and turn off the nightlight if you can. Sleeping in a very dark place helps your baby’s body get quality deep sleep more quickly, and consistently having a dark place helps train your little one’s body that dark places are restful places.
  2. Keep wakeful time bright: On the flip-side of that, your awake time should be full of as much sunlight as early as possible. So open those curtains and raise the blinds to let the sunshine in! You can also try going on a walk outside first thing in the morning to help get that dose of Vitamin D while training your baby’s body that brightness means wakefulness.
  3. Cut the artificial lights: Start by dimming the lights about an hour before bedtime or leave the lights off altogether and let the light dim naturally as the sun goes down. Also, try to limit the baby’s exposure to the light emitted by screens such as the television. And if you can get away with it, nix the nightlight completely. If going nightlightless isn’t an option for you, look for one with a blue light filter.
  4. Follow a routine: The circadian rhythm is all about routines – after all, the sun waits for no one! Try to follow a daily and nightly schedule as best as you can. That means lots of sunshine from early on in the day, being mindful of wake windows, and creating a soothing bedtime routine that lasts no more than 30 minutes. Things you can incorporate into the bedtime routine include dimming the lights, listening to soft music or sounds, reading stories quietly, and a warm bath or infant massage.
  5. Mind the wake windows: A “wake window” is the ideal length of time a child is awake between sleeping sessions. For a two-month-old, the wake window is about an hour. That means that once your newborn wakes up, you’ve got about an hour of playtime before your baby starts to get drowsy. Keep your little one up much longer than that, and you risk your baby getting overtired. As your baby gets older, their wake window lengthens to one and a half hours by four months and three hours by six months. By keeping track of how long your baby is awake, you can keep them from getting overly tired, and you get them primed to sleep for longer stretches at night.

Most new parents find themselves with a newborn that won’t sleep through the night, and that’s ok! As babies get older, they develop a circadian rhythm that lets both parents and baby get a good night’s sleep. By keeping our five tips in mind as your baby grows, you set them up for sleeping success right from the start.