15/10/2026
What can we take from this new research when looking at a baby’s sleep?
Researchers analysed parent-recorded sleep logs from over 175,000 babies aged 3–18 months, collected through the Napper app.
Daytime sleep reduced with age, averaging around 3 hours 46 minutes at 3 months, 2 hours 7 minutes at 12 months and 1 hour 41 minutes at 18 months.
These are averages, not amounts every baby should be having.
Around nap transitions the remaining naps generally became longer. However, they didn’t fully maintain the previous daytime sleep total. A transition can therefore involve both a redistribution of sleep and a reduction in daytime sleep.
The move from two naps to one showed the greatest variation in timing. The median was approximately 13.2 months, but this isn’t a deadline for dropping a nap.
More daytime sleep was associated with later bedtimes and shorter bedtime to-morning intervals.
This doesn’t prove that cutting naps improves nights. The study couldn’t establish cause and effect, or whether more daytime sleep led to shorter nights, or vice versa.
Bedtimes became more consistent with age, with a greater change before 9 months. The authors interpreted this as consistent with circadian development. However, they didn’t directly measure biological circadian rhythms, and family routines could also contribute.
An important detail is time awake overnight wasn’t subtracted from the totals. The overnight figures describe the interval between bedtime and morning waking, rather than actual sleep. They cannot tell us exactly how much sleep the babies got or needed.
The middle column in these slides is my practical interpretation. The study didn’t test an ideal routine, nap restriction or sleep training.
For transparency, the sample consisted of Napper app users and one author is employed by Napper. This doesn’t invalidate the findings but it is relevant when considering how widely they apply.
The reason I chose to share this research is in its value in explaining familiar advice more clearly, rather than presenting a major new discovery.