HormonesMelatonin

Delayed estimated circadian phase is associated with greater restless legs syndrome symptom severity

In an exploratory pilot study of 21 patients with idiopathic RLS and 21 matched insomnia controls, patients with RLS showed a non-significant trend toward delayed estimated dim light melatonin onset (eDLMO) compared to controls (10:01 PM vs 9:33 PM, p=0.069, d=0.58). Within the RLS group, later eDLMO was modestly associated with higher RLS symptom severity scores (β=0.0726, p=0.038) after adjusting for age and depressive symptoms.

Last updated: Jul 25, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score43/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Circadian Rhythm in Restless Legs Syndrome and Its Association With Symptom Severity: An Actigraphy-Based Study.

observational

Bang SY, Awan A, Lim D, Hwang S, Koo BB, Kim JK, Jung KY · Journal of biological rhythms (2026)

Participants: N/A
Duration: 14 days
Intervention: None (observational study comparing RLS patients to insomnia controls using actigraphy-based eDLMO estimation)
Outcome: Estimated dim light melatonin onset (eDLMO) and RLS symptom severity (IRLS score)
Effect Size: Cohen's d=0.58 for eDLMO difference between groups
Population: Patients with idiopathic restless legs syndrome (mean age 61.2 years, 90% female) and age- and sex-matched chronic insomnia controls

Result:

PubMed: 42417186DOI: 10.1177/07487304261456963

Mechanism Graph

Circadian phase delay may alter melatonin timing and neurotransmitter regulation
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Delayed circadian phase could exacerbate evening symptom onset in RLS
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Later eDLMO correlates with higher IRLS scores
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Supports a link between circadian phase delay and clinical burden in RLS

Limitations

  • ⚠Exploratory pilot study with small sample size (n=21 per group)
  • ⚠eDLMO estimated from actigraphy model rather than direct salivary melatonin measurement

Frequently Asked Questions

What is eDLMO and how was it measured?▼

eDLMO stands for estimated dim light melatonin onset, which was derived from a mathematical model based on 14 days of wrist actigraphy data, not from direct melatonin sampling.

Was the circadian phase difference between RLS and insomnia groups statistically significant?▼

No, the difference was a non-significant trend (p=0.069) with a moderate effect size (Cohen's d=0.58).

Does this study prove that circadian delay causes worse RLS symptoms?▼

No, the study shows a modest association (β=0.0726, p=0.038) but cannot establish causality due to its observational and exploratory design.

What was the sample size and demographic of the study?▼

The study included 21 RLS patients and 21 insomnia controls, both groups with mean age around 61 years and 90% female.

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References

  1. 1.Bang SY, Awan A, Lim D, Hwang S, Koo BB, Kim JK, Jung KY. "Circadian Rhythm in Restless Legs Syndrome and Its Association With Symptom Severity: An Actigraphy-Based Study.." Journal of biological rhythms, 2026. PMID: 42417186 DOI: 10.1177/07487304261456963
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.