Understanding your baby’s “sleep window” is one of the keys to helping a baby learn to sleep independently. Getting your baby down in their sleep window (i.e. before they become overtired) will keep crying to a minimum and allow your baby to go to sleep on their own with a relative amount of ease.
So what exactly is a sleep window?? A sleep window is that “sweet spot” when your baby will go to sleep most easily. It is a place in your baby’s natural circadian rhythms when they have just begun getting sleepy and are BEGINNING to feel tired but they are not yet OVER tired. The problem with a baby’s sleep window is that it is extremely easy to miss, unless you are actively looking for it. Especially when your baby is young. You may only have about 5 minutes (or less!) to get your baby down for his nap or bedtime before you have an over tired, crying baby on your hands! This is also, many times the reason for a false start at bedtime. Here is a chart to help you understand what the average wake window is for your age baby.

The older a baby gets the more pronounced his sleepy signs usually get. Unless your baby is chronically overtired, in which case your baby may seem to stay awake for hours with no obvious sleepy signs. This happens because cortisol is elevated and one of cortisol’s jobs is to wake us up or keep us awake. Obviously, this is NOT what we want for our babies! Cortisol is a stress hormone and when our babies don’t go to sleep when they are tired they will cross over into the land of being overtired and when this happens cortisol elevates to keep them awake. This is why you feel your baby is fighting sleep! It’s actually the cortisol in their body that is keeping them from sleeping.
This is why watching for sleepy signs is important. Typical sleepy signs that most baby’s exhibit are as follows: Yawning, fussiness, red eyes, red eyebrows, glazed eyes, avoiding eye contact, rubbing eyes, heavy eyelids, etc. When you have a young baby, (younger than 6 weeks) you may need to watch your baby even more closely so as not to miss his sleep window. Many times young babies have a tendency to just close their eyes and go to sleep. That is fine as long as some of the time you are actively seeking to lay them down in their crib relaxed and sleepy but awake. Young babies can also exhibit no sleepy signs and because of this as a new parent you often end up missing their sleep window, This is why we must keep an eye on the clock as well as our babies.
Understanding how long your baby should be able to stay awake comfortably is SOO important! This allows you to use the clock as a guide as well as watch your baby for sleepy signs. Utilizing BOTH of these tools (your baby AND the clock) helps you to make sure that you stay on top of your baby’s sleep window and your baby doesn’t cross over into the dreaded overtired zone. Starting your baby on a flexible routine makes watching for sleepy signs SO much easier!
Staying On Top of Sleepy Signs
Recognizing AND staying on top of sleepy signs is one of the most important things to learn as you are seeking to understand your baby. Getting the timing right for naps and bedtime will go a long way in helping your baby go to sleep and STAY asleep. Now, who doesn’t want that!??
Unfortunately, many times moms don’t know how to “read” their young baby. Baby is fussing because they are tired and need to be put down, but mom feels like they haven’t been awake for very long so she tries to feed her baby again or rock or bounce or sing. More often than not this keeps a baby awake instead of meeting their need for sleep. This generally leads to an overtired baby who is either now crying uncontrollably or is wide-eyed and “wired” and won’t go to sleep no matter how hard mom tries! Most new moms GREATLY overestimate how long their baby can comfortably stay awake. This can lead to sleep struggles within a few short weeks.
Keeping a daily log of your baby’s eating and sleeping patterns is a good way to start learning your baby sooner rather than later. You should start to see patterns develop as to how long your baby can comfortably stay awake before he starts showing sleepy signs. By the time a baby is about 3 months old they can usually comfortably stay awake for approximately 1:15-1:30 hours (this includes feeding time). The exception to this would be the first wake time of the day which may still be closer to 1 hour or 1 hour 15 minutes. Understanding your baby’s sleep window will help you to better understand your baby and meet his need for sleep. Starting a bedtime routine for your baby somewhere between 4-6 weeks is also SUPER helpful!
If your baby is still struggling to go to sleep independently and you feel like you need some extra help or just have more questions, reach out to me! I’m here to help as you navigate laying a healthy sleep foundation in those early months.
Looking for more great resources from Mamie?
How and Why to Create a Bedtime Routine for Your Baby