Sleep Pressure in Babies- A Guide
Sleep pressure is a term parents come around when sleep training their child. For babies, this is defined as the internal buildup of tiredness that happens the longer they are awake. It’s a biological process that leads to a physical need for sleep. Depending on their environment, stimulation, noise, lighting, this pressure can build slowly or hit a tipping point fast.
You will notice that the more energy a baby exerts during their wake windows, the longer their typical sleep schedule will be.
The Wake Window When Sleep Training
Babies grow their stamina gradually as they age. The average wake window for a 4- to 6‑month-old is about 2.5 to 3 hours according to Dr. Daniel Golshevsky (Dr. Golly), author of the comprehensive guide Baby Wake Windows by Age. A quick summary of his findings are as follows:
Wake Windows by Age (Dr. Golly’s Guide)
0–6 weeks: 45 to 60 minutes
6–12 weeks: 1 to 1.5 hours
3–4 months: 1.5 to 2 hours
4–6 months: 2.5 to 3 hours
6–9 months: 2.5 to 3.5 hours
9–12 months: 3 to 4 hours
12–18 months: 4 to 6 hours
18 months – 2 years: 5 to 6 hours
2 years+: 5.5 to 7 hours
Natural wake window extensions can also be built through environmental changes: moving your baby to a new room, introducing new toys, getting fresh air, using soft sounds or songs, and gently shifting stimulation can help prolong their awake time and build stamina more steadily.
Is it Sleep Pressure or is Your Baby Overtired?
If you're worried your baby is overtired, watch for the signs. According to Emma Hubbard, BScOT, a certified pediatric sleep consultant and occupational therapist, tiredness builds in stages.
First signs of tiredness:
Sleepy eyes
Slower blinking
Less interest in people and toys
Later signs include:
Jerking body movements
Frowning
Yawning
General fussiness
Rubbing eyes
Sucking on fingers
To prevent overtiring your baby, it is ideal to have them sleep anywhere on our between these two phases. The later stage signs are normally due to your abby being overtired. Crying tends to show up after these signs, not before. If your baby is already crying and stiffening their body, they’ve likely passed the ideal sleep window. Sleep pressure has turned into stress, and sleep is now much harder to come by.
Why You Shouldn’t Let Your Baby Cry Itself to Sleep
The common and traditional family advice is: “Just let them cry themselves to sleep.” But this method can backfire, especially if your baby is already overtired.
When that happens, their body releases cortisol and adrenaline, two stress hormones that disrupt the body’s ability to relax. As Healthline reports, an overtired baby is often stuck in a hormonal cycle that actively works against sleep. Even if they eventually pass out, it may not be restful sleep. It also often leads to shorter naps and increased night wakings.
Synchronizing Yourself to Your Baby’s Sleep Patterns
Using this guide, you can better recognize whether your baby’s sleep pressure is building naturally or has moved into overtired territory. The key is to catch that mid-window, when your baby is tired enough to fall asleep but not so overstimulated that their stress response is triggered.
Look at how long your baby stays awake between naps, track repeated signs, and aim to respond before crying begins. Every baby has a rhythm, and learning to spot it is more effective than trying to force sleep through crying.
Get a Certified Pediatric Sleep Expert
Letting your baby cry themselves to sleep doesn’t teach them to self-soothe. Instead, this can cause dysregulation due to their stress levels maxing out and resulting in more unpredictable sleep patterns. Hormonal disruption leads to shorter naps, inconsistent night sleep, and slower development of their wake window stamina.
If it seems like your baby just won't go to sleep, you may need additional support and guidance to re-regulate their sleep cycle. Connect with a certified pediatric sleep expert on demand through MissPoppins.