Impact of daytime naps on children's sleep quality uncertain

“Daytime naps ‘should stop at the age of two’: Children have poorer quality sleep if they rest during the afternoon,” is the inaccurate headline on the Mail Online.

Researchers have pooled all of the available evidence on the effects of napping in childhood.

As they acknowledge, many of the studies were of a poor quality due to lack of reliable evidence.

Out of the 26 studies, just one looked at the effect of napping on sleep in children under the age of three. It found that napping was associated with a shorter night’s sleep in children over the age of two. This study did not assess the quality of sleep.

The quality of sleep was assessed in three studies of children over the age of three. The quality of sleep was found to be reduced in those that napped.

Across the other studies, there were no clear findings on the effects of napping in terms of behaviour, cognitive function or physical health, regardless of age.

The review does not support the notion that parents should automatically stop their children from napping after their second birthday. It actually calls for more rigorous research in this area, so firmer conclusions can be drawn.

We would tentatively suggest that, based on the lack of evidence, the best people to decide whether an individual child benefits from an afternoon nap are the parents.

Where did the story come from?

The study was carried out by researchers from Queensland University of Technology and James Cook University in Queensland. No external funding was reported.

The study was published in the peer-reviewed medical journal Archives of Disease in Childhood.

Mail Online’s reporting of the study is poor and may cause unnecessary alarm among parents.

The paper took the findings from just one of the studies and produced a dramatic headline that naps should stop at the age of two.

This is not a recommendation from the review, which actually found that an association between daytime napping and later onset of sleep, shorter duration and poorer quality sleep was found in children over the age of three.

The review is clear that these findings were based on poor-quality studies, so are not reliable.

There is huge variation in children’s sleeping patterns and requirements, with children naturally growing out of the need for naps at different rates. This review highlights the need for better studies in this area, rather than a blanket cut-off age for all.

What kind of research was this?

This was a systematic review of all studies that have assessed the effect of napping on child health and development.

The authors highlight the ongoing debate on the optimal amount of sleep recommended in early childhood. Previous research had looked at the overall amount of sleep in a 24-hour period and the effect this had on children’s health. The authors say this influenced the promotion of napping, to make up the optimal number of hours. However, this does not take into account the effect napping may have on the quality and length of night-time sleep. The aim of this study was to see what effect napping had on a child’s night-time sleep, behaviour, cognitive functioning (ability to think and reason), and physical health.

What did the research involve?

The researchers searched six databases for any type of study that has looked at the effects of napping in children from birth up to the age of five. They then examined the reference lists of any relevant studies, to ensure they had not missed any.

The quality of each study was assessed using the internationally recognised GRADE system. This is an ongoing attempt to achieve a consensus on what represents high-, medium- or low-quality evidence.

In general, randomised controlled trials (RCTs) are rated as high-quality and observational studies as low-quality, though this also depends on the methodology. It takes into account the number of participants and the risk of the studies being biased.

Due to the fact that young children lack the capacity to consent to take part in studies involving specific interventions (such as making them stay awake during the day), there were no RCTs on napping available for analysis.

What were the basic results?

There were 26 studies that met the inclusion criteria. All were low-quality and none were RCTs, for the reasons discussed above.

With regards to night-time sleep:

• one Japanese study of 967 children found there was no difference in night-time sleep when associated with the duration of napping in children younger than two; children older than two had later onset of sleep and less night-time sleep after napping
• two additional studies of children aged between three-and-a-half and seven found napping was associated with later onset of night-time sleep
• four studies of children aged three or more found reduced night-time sleep duration after napping
• three studies of children aged three or more found poorer quality of sleep after napping

Behaviour and cognitive outcomes in children who nap compared to those who don’t were mixed across the studies, which were carried out on children from birth to age seven.

Similarly, there was very poor evidence available of the effect of naps or no naps on physical health at any age. 

How did the researchers interpret the results?

The authors say “the evidence indicates that beyond the age of two years, napping is associated with later night sleep onset and both reduced sleep quality and duration”. They say that “the evidence regarding behaviour, health and cognition is less certain”. They suggest that “in preschool children presenting with sleep problems, clinicians should investigate napping patterns”.

Conclusion

This systematic review has found that the available evidence on the effect of napping on young children is poor. One study found that in children aged over two years, naps were associated with later sleep onset and shorter duration. The rest of the studies assessing night-time sleep were in children over the age of three. In these children, naps were associated with later onset of night-time sleep, with shorter duration and poorer quality.

There was no clear evidence of the effect of having naps or not having naps on behaviour, cognitive function or physical health.

While systematic reviews cover all of the evidence available for a particular question, they are limited by the quality of the available studies. This analysis is restricted to the facts reported by the systematic review and does not independently assess the quality of the included studies.

With this in mind, none of the studies were RCTs. The findings of this review need to be taken within the context of their poor quality, which limits the reliability of the findings. Five of the nine studies looking at the effect of naps on sleep were scored the lowest possible score for quality. The main issues reported were that the studies:

• analysed less than seven days of sleep data
• relied on parental report, rather than direct observation
• had a small sample size

There is huge variation in children’s sleeping patterns and requirements, with children naturally growing out of the need for naps at different rates. This review highlights the need for better studies in this area, rather than a blanket cut-off age for all.

Due to the paucity of high-quality evidence, we would certainly not recommend changing your child’s sleeping patterns if it seems to suit them.

Read about common sleep problems in children

Analysis by Bazian. Edited by NHS Choices.  Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Daytime naps ‘should stop at the age of two’: Children have poorer quality sleep if they rest during the afternoon. Mail Online, February 18 2015

Links To Science

Thorpe K, Staton S, Sawyer E, et al. Napping, development and health from 0 to 5 years: a systematic review. Archives of Disease in Childhood. Published online February 17 2015