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Personalized online counselling based on cognitive behavioral principles does not significantly improve sleep efficiency in shift workers compared to sleep diary completion alone.

In a randomized controlled trial of 66 German shift workers, both the intervention group receiving four personalized counselling messages and weekly sleep diaries and the control group completing only sleep diaries showed significant improvements in sleep efficiency, insomnia symptoms, and depression symptoms over four weeks. However, the improvements were not significantly greater in the intervention group than in the control group, failing to demonstrate superiority of the counselling intervention. Daytime sleepiness did not improve in either group.

Last updated: Aug 2, 2026•1 RCTs•📖 Read as article →

Evidence Score

Evidence Score48/100
Human RCT★★☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Efficacy of an anonymous, preventive, personalized online counselling to improve shift workers' sleep quality: a randomized controlled trial.

observational

Retzer L, Graessel E, Feil M, Lehmann R, Stemmler M, Richter K · Scientific reports (2026)

Participants: N/A
Duration: 4 weeks
Intervention: Four personalized online counselling messages based on cognitive behavioral principles, plus four weekly sleep diaries
Outcome: Sleep efficiency (primary), symptoms of insomnia and depression (secondary), daytime sleepiness
Effect Size: N/A (no significant between-group difference reported)
Population: German shift workers from various industries with sleep complaints

Result:

PubMed: 42527422DOI: 10.1038/s41598-026-64210-7

Mechanism Graph

Participants received personalized counselling messages adapted to shift work
↓
Participants completed weekly sleep diaries
↓
Control group completed sleep diaries only
↓
Both groups showed improvements, but no significant difference between groups

Limitations

  • ⚠Small sample size (n=66 in Intention to Treat sample)
  • ⚠Short four-week time frame
  • ⚠Control group's sleep diary completion may have had therapeutic effects, confounding results

Frequently Asked Questions

Did the online counselling improve sleep efficiency in shift workers?▼

Both the counselling and control groups showed significant improvements in sleep efficiency, but the counselling was not significantly better than just completing sleep diaries.

What was the primary outcome measured in this study?▼

The primary outcome was sleep efficiency, measured via sleep diaries.

Who were the participants in this trial?▼

The participants were German shift workers from various industries, recruited through an anonymous online platform.

Why might the control group have improved?▼

The control group completed weekly sleep diaries, which may have had a therapeutic effect by increasing self-monitoring and awareness of sleep patterns.

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References

  1. 1.Retzer L, Graessel E, Feil M, Lehmann R, Stemmler M, Richter K. "Efficacy of an anonymous, preventive, personalized online counselling to improve shift workers' sleep quality: a randomized controlled trial.." Scientific reports, 2026. PMID: 42527422 DOI: 10.1038/s41598-026-64210-7
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.