This meta-analysis of 66 studies involving 2947 healthy children provides pooled normative polysomnographic data for 34 parameters, demonstrating significant age-related changes in sleep architecture, arousal, and cardiorespiratory measures, with sex influencing only sleep latency.
Key Findings
Methods
A total of 66 studies with 2947 healthy children were eligible for inclusion after screening 3612 articles.
Systematic search was conducted in Web of Science and Scopus.
Studies were required to use American Academy of Sleep Medicine (AASM) criteria (2007 or 2012) for scoring polysomnographic parameters.
Children with previously diagnosed health conditions were excluded.
Pooled estimates and 95% confidence intervals were established for 34 polysomnographic parameters.
A random-effects meta-analysis model was used for pooling estimates.
Results
Multiple sleep architecture parameters showed age-related decreases in healthy children.
Total sleep time (TST), sleep period time, TST in stage N3, and TST in REM all decreased with increasing age.
Number of sleep cycles also decreased with age.
These findings were identified through meta-regression analysis assessing the influence of age on pooled parameters.
The number of awakenings and TST in stage N2 increased with age, indicating a shift in sleep stage distribution.
Results
The number of stage shifts and SpO2 nadir increased with age, while mean SpO2 and mean heart rate during sleep and REM decreased with age.
SpO2 nadir (the lowest oxygen saturation recorded) increased with age, suggesting improved oxygenation at the nadir as children grow older.
Mean peripheral oxygen saturation (SpO2) during sleep decreased with age.
Mean heart rate during both overall sleep and REM sleep decreased with increasing age.
Number of stage shifts increased with age, indicating more fragmented sleep architecture in older children.
Results
Arousal and leg movement parameters showed age-related decreases in healthy children.
Total arousals decreased with age.
Total leg movements decreased with age.
Periodic leg movement index also decreased with age.
These parameters were assessed via meta-regression for the influence of age.
Results
Cardiorespiratory parameters including central apnoea index and apnoea-hypopnoea index (AHI) decreased with age.
Both central apnoea index and AHI showed age-related decreases.
This suggests that respiratory events during sleep are more common in younger children and decline as children age.
These normative values can serve as control values for clinical and research contexts.
Results
Sleep latency was the only polysomnographic parameter significantly influenced by sex.
Sleep latency changed by -1.27 minutes per 10% increase in the proportion of males in a study sample.
This indicates that males had shorter sleep latency compared to females.
No other of the 34 polysomnographic parameters showed a statistically significant influence of sex.
Sex influence was assessed using meta-regression alongside age.
Conclusions
This meta-analysis establishes the first comprehensive set of normative polysomnographic reference values for the pediatric population scored using recent AASM criteria.
Prior to this study, normative values for polysomnographic parameters in childhood were lacking.
Normative data cover 34 parameters spanning sleep architecture, arousals, leg movements, and cardiorespiratory measures.
The authors note these values can be used as control values in both clinical and research contexts.
Scoring was standardized to AASM 2007 or 2012 criteria to ensure comparability across studies.
What This Means
This research systematically combined data from 66 studies involving nearly 3,000 healthy children to create a comprehensive reference guide for what is 'normal' during a sleep study (polysomnography) in kids. Sleep studies measure many things at once — brain activity, breathing, oxygen levels, heart rate, and leg movements — but until now, there were no well-established normal ranges for children that accounted for how these measures change as kids grow older. By pooling all available studies that used standardized scoring methods, the researchers were able to calculate average values and normal ranges for 34 different sleep measurements across childhood.
The study found that many aspects of sleep change significantly with age. For example, younger children tend to sleep longer, spend more time in deep sleep (N3) and REM sleep, and have more breathing events and leg movements during sleep than older children. As children get older, they tend to wake up more during the night, spend more time in lighter sleep (N2), and have more transitions between sleep stages. Heart rate during sleep also naturally decreases with age. Interestingly, of all 34 parameters examined, only sleep latency (the time it takes to fall asleep) was influenced by sex, with boys falling asleep slightly faster than girls.
This research matters because clinicians who perform sleep studies on children have long lacked reliable reference values to determine whether a child's results are abnormal. Without knowing what is 'normal' for a given age, it is difficult to diagnose conditions like sleep apnea or periodic limb movement disorder accurately in children. These new normative values provide a practical tool for both doctors evaluating individual patients and researchers designing studies, helping to improve the diagnosis and understanding of sleep disorders in children.
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Van Eyck A, de Caen G, Bokhaut J, Blinder H, Bouziotis J, Katz S, et al.. (2026). Normal polysomnography parameters in healthy children: a systematic review and meta-analysis.. European respiratory review : an official journal of the European Respiratory Society. https://doi.org/10.1183/16000617.0224-2025