Improve Your Baby’s Sleep by Understanding the Science of Sleep
Updated: Aug 4, 2022
Trying to figure out your child’s sleep schedules can sometimes feel a little overwhelming. It’s also easy to feel responsibility and pressure around when and how our child is sleeping. If they didn’t sleep well, then we blame ourselves.
Well let’s take a step back and talk a bit about the science of sleep, particularly for children. I think this is so intriguing and it helps to set the stage for how we approach our child’s sleep. It also helps to take out some of the emotion around sleep. There’s some important biological factors that influence our children’s sleep, and knowing these factors can really help us to set up the right schedule and pay attention to the right cues, so that we can get our children really good restorative sleep.
You’ve probably heard about circadian rhythms. But let’s talk about this as it relates to babies. Circadian rhythms are our internal body clock that has natural fluctuations over 24 hours. These rhythms become developed in babies between 3-4 months of age. Digestion, hormones, body temperature, moods, metabolic rate, sleep and more are all influenced by this internal body clock. The most important factor that resets our body’s clock each day is sunlight.
What’s so interesting to me is that the part of the brain that regulates sleep is located just above our brain’s optic nerves. Because of this, light and darkness are critically important to the regulation of our circadian rhythms. When our brain
perceives light, it triggers a series of hormonal releases which kicks our body into gear for the day. Light cues the brain to wake up. When darkness is perceived, our brain releases a sleepy hormone called melatonin. This relaxes the body for sleep and helps to regulate the timing of sleep.
So when we talk about an optimal sleep environment for our babies, we want it to essentially mimic what our child’s body is doing when they’re sleeping. Knowing that darkness promotes melatonin (the sleepy hormone), we want our baby’s room as dark as possible. When I say dark, I mean dark. Some parents are often concerned that their baby would be scared of the dark, but they just aren’t developmentally mature enough in the first year or two to be scared of the dark. We also want the room to be comfortably cool (around 68 degrees Fahrenheit) - as our babies fall asleep, their core body temperature drops, so again, we’re helping to mimic what their body is already doing.
In addition to these sleep rhythms, our babies build up their drive to sleep while they are awake. Think of a balloon filing with air. When they reach a peak of “sleep pressure” that’s the optimal time to have them fall asleep. As we pass this point, our babies then become overtired and it is hard for them to fall asleep and stay asleep. You may often hear me talk about overtiredness. I don’t want you to obsess over the exact minute to time your child’s sleep, but we do want to really hone into their sleepy cues to try and time their sleep as best we can around their sleep drive. When we time our baby’s sleep when their sleep pressure and circadian rhythms align this is the sweet spot and gives the most likelihood of them having high quality restorative sleep. When our children’s schedule is inconsistent and we time their sleep at the wrong times, it’s not high quality sleep and perpetuates a cycle of overtiredness.
Lastly, it’s helpful to know that children get their most restorative sleep in the first half of the night. If we put our children to sleep later, it doesn’t shift when they get that deep sleep, they just miss out on some of it. I wish I had known this years ago! So never be afraid of an early bedtime, particularly if daytime sleep hasn’t been great. You’re helping your baby get more of that high quality restorative sleep which also helps to set up the second half of the night.