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Sleep-timing mismatch (MSFsc-lights-off interval) predicts poorer objective sleep initiation, continuity, and REM architecture in a clinical population under a fixed laboratory schedule

In 645 clinically referred adults undergoing polysomnography under a fixed schedule (lights-off 21:30, lights-on 06:00), a greater mismatch between individual sleep midpoint (MSFsc) and lights-off time was independently associated with longer sleep onset latency, lower sleep efficiency, higher N1 sleep, and lower REM percentage. These associations were most pronounced in patients with later MSFsc and remained significant after adjusting for age, sex, BMI, AHI, and insomnia severity.

Last updated: Jul 14, 2026โ€ข0 RCTsโ€ข๐Ÿ“– Read as article โ†’

Evidence Score

Evidence Score34/100
Human RCTโ˜†โ˜†โ˜†โ˜†โ˜†
Meta-analysisโ˜†โ˜†โ˜†โ˜†โ˜†
Mechanismโ˜…โ˜…โ˜…โ˜…โ˜…
Safetyโ˜…โ˜…โ˜…โ˜…โ˜†
Confidencelow

Study Evidence

Study 1. Sleep-timing mismatch (MSFsc-lights-off interval) and its association with polysomnographic sleep parameters in a clinical population under a fixed laboratory schedule.

observational

Wongprakarnsanti K, Siritienthong J, Awirutworakul T, Sukying C, Wisajun P ยท Sleep medicine (2026)

Participants: N/A
Duration: single overnight PSG
Intervention: Sleep-timing mismatch (ฮ” t) defined as the difference between MSFsc and individually recorded lights-off time
Outcome: Polysomnographic sleep parameters: sleep onset latency, sleep efficiency, N1 sleep percentage, REM percentage
Effect Size: N/A (correlation and regression coefficients not specified in abstract)
Population: 645 clinically referred adults (enriched for obstructive sleep apnea evaluation) under a fixed laboratory schedule

Result:

PubMed: 42419039DOI: 10.1016/j.sleep.2026.109112

Mechanism Graph

Later chronotype (later MSFsc) creates greater mismatch with fixed early bedtime
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Mismatch leads to difficulty initiating sleep at forced early time
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Results in prolonged sleep onset latency and fragmented sleep architecture
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Reduced sleep consolidation and lower REM percentage

Limitations

  • โš Abstract does not report exact effect sizes or confidence intervals
  • โš Study population enriched for OSA may limit generalizability to other clinical groups
  • โš Cross-sectional design precludes causal inference

Frequently Asked Questions

What is MSFsc?โ–ผ

MSFsc stands for mid-sleep on free days corrected for sleep debt, a measure of chronotype or individual sleep timing preference.

How was sleep-timing mismatch calculated?โ–ผ

The mismatch (ฮ”t) was defined as the difference between each participant's MSFsc and their individually recorded lights-off time in the lab.

Did the study control for sleep apnea severity?โ–ผ

Yes, the analyses were adjusted for AHI (apnea-hypopnea index) along with age, sex, BMI, and insomnia severity.

Is this finding relevant for people without sleep disorders?โ–ผ

The study was conducted in a clinical population with high OSA prevalence, so direct applicability to healthy individuals is uncertain.

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References

  1. 1.Wongprakarnsanti K, Siritienthong J, Awirutworakul T, Sukying C, Wisajun P. "Sleep-timing mismatch (MSFsc-lights-off interval) and its association with polysomnographic sleep parameters in a clinical population under a fixed laboratory schedule.." Sleep medicine, 2026. PMID: 42419039 DOI: 10.1016/j.sleep.2026.109112
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