Someone told you to keep your newborn awake during the day.

The logic seemed plausible: if they sleep less during the day, they’ll be more tired at night and sleep longer. You’re already exhausted. You’ll try anything. So you’ve been keeping the lights on, doing whatever you can to prevent daytime naps, waiting for the night-time payoff.

It hasn’t come.

Here’s why — and what actually helps instead.

For the full guide on day/night confusion, see Day/Night Confusion in Newborns: What It Is and How to Help. For the science of how the body clock develops, read How Babies Develop a Body Clock.

The myth

“Keep them up during the day and they’ll sleep at night.”

This advice applies reasonable adult logic — if I’m more tired, I sleep better — to a baby physiology that doesn’t work the same way. For adults, building sleep pressure through extended wakefulness can shift sleep timing. For newborns, it produces something completely different: overtiredness. And overtired newborns don’t sleep better. They sleep worse.

Why it backfires

Newborns cannot sustain long wake periods. A newborn’s maximum comfortable wakefulness window is often 45–90 minutes. This is not a training failure or a sign of something wrong — it is the developmental capacity of a very new nervous system. The brain cannot sustain the alert, wakeful state for longer than this without significant stress.

Overtiredness raises cortisol. When a newborn is kept awake past their comfortable window, their body treats the accumulated sleep deprivation as a physiological stressor. The response is a cortisol release — the same hormone released in response to threat or stress. Cortisol is stimulating and wake-promoting. The more overtired the baby becomes, the more cortisol, the more wired and harder to settle they become.

Cortisol disrupts sleep. Elevated cortisol at sleep onset makes it harder to fall asleep and harder to stay asleep. The overtired newborn who has been kept awake all afternoon is not primed for a long, restful night. They are primed for fragmented, difficult, cortisol-disrupted sleep — with more frequent waking, not less.

The practical outcome of keeping a newborn awake during the day is a baby who is harder to settle in the evening, wakes more frequently overnight, and may actually produce shorter, poorer-quality night sleep than a baby who was allowed to nap freely.

Why day/night confusion doesn’t work this way

The deeper issue is that day/night confusion is not a sleep pressure problem — it’s a circadian development problem.

Day/night confusion occurs because the newborn’s circadian clock is not yet calibrated. Their internal system does not yet distinguish day from night. No amount of sleep pressure manipulation changes this. You cannot fix an uncalibrated clock by adjusting how tired the baby is. The clock is not responding to tiredness — it is responding (gradually, as it matures) to light.

The approach that actually supports the developing circadian system is:

  • Providing daylight during the day — to give the developing clock its primary calibration signal
  • Allowing free daytime napping — to prevent the overtiredness that disrupts all sleep
  • Making nights dark and boring — to reinforce the contrast between day and night

Preventing daytime sleep addresses none of the underlying circadian mechanism and creates the cortisol problem on top of it.

What about waking for feeds?

There is a legitimate reason to wake a newborn during the day in some circumstances: if they are sleeping very long stretches during the day and a healthcare professional has recommended waking for feeds to support weight gain. In the early weeks, some newborns need to be woken every 2–4 hours to feed regardless of sleep state, particularly if they are small, jaundiced, or slow to regain birthweight.

This is different from keeping a newborn awake to build sleep pressure. Waking for feeds has a specific medical rationale. Keeping them awake between feeds to tire them out does not.

If you are unsure whether to wake your newborn for feeds, ask your midwife or health visitor — they can advise based on your baby’s specific weight gain and feeding pattern.

What to do instead

Let your newborn sleep during the day when they signal tiredness. Watch for tired cues — yawning, eye rubbing, going quiet, losing interest in what’s around them — and respond to them. A newborn who is allowed to nap freely during the day is better rested, less cortisol-loaded, and easier to settle at night.

Expose them to daylight. This is the one active thing that genuinely supports circadian development. Morning light in particular — outdoors or near a window — provides the zeitgeber signal that helps the developing clock calibrate toward day. Naps in normally lit rooms (rather than full blackout) reinforce the day signal.

Make nights boring. Dark, quiet, minimal stimulation for all night wakings. The contrast between stimulating days and dull nights is what teaches the developing clock the difference.

Wait. Day/night confusion resolves at six to twelve weeks for most babies. The clock is developing. You cannot rush it. You can support it and survive it — and they are not the same thing.

The bottom line

Keeping your newborn awake during the day to fix nights is one of those pieces of advice that sounds logical and isn’t. It conflates sleep pressure with circadian timing, ignores newborn physiology, and consistently produces the opposite of the intended result.

Let them sleep during the day. Give them light. Make nights boring. And trust that the clock — which is developing on its own biological schedule — will find its way.

References: see the main day/night confusion guide for full citations.