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Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
A Journey Through Chronotype Changes in University Students
Esther D Domenie1,2, Davide Erminelli1, Gianluca Giusti1,3
1Department of Medicine, University of Padova, Padova, Italy.
Journal of Biological Rhythms
|May 11, 2026
Summary
Chronotype shows relative stability in young adults but can shift, especially with behavioral advice. About 30% of students changed their self-assessed chronotype category over time.
Area of Science:
- Chronobiology
- Sleep Science
- Behavioral Science
Background:
- Chronotype, an individual's preferred sleep-wake timing, is generally considered stable but can fluctuate.
- University students experience unique academic year constraints impacting sleep patterns.
- Circadian hygiene education aims to improve sleep timing and consistency.
Purpose of the Study:
- To investigate the temporal stability of self-assessed chronotype in university students.
- To examine how behavioral advice on sleep, meal, and exercise timing affects chronotype.
- To analyze changes in chronotype measures like midsleep and social jetlag over time.
Main Methods:
- A large cohort of university students participated in a 2-arm circadian hygiene education initiative.
- Chronotype was assessed using the Self-Morningness/Eveningness (Self-ME) question and the Ultrashort Munich ChronoType Questionnaire (μMCTQ).
- Repeated assessments were conducted over 2-22 months, with sample sizes ranging from 1902 to 2820 participants.
Main Results:
- Good agreement was found between subsequent Self-ME assessments (Cohen's k between 0.6-0.8), with ~70% confirming their initial category at 2 months.
- Approximately 30% of participants changed chronotype categories, with those who moved once being more likely to move again.
- Midsleep and social jetlag showed yearly variations, and circadian hygiene interventions had slight, differential effects on chronotype stability.
Conclusions:
- Chronotype in young adults is relatively stable but exhibits plasticity within certain limits.
- Chronotype stability is influenced by measurement methods and behavioral interventions.
- The academic year's structure impacts student sleep timing, affecting chronotype measures.
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