Chronotype Assessment and Sleep Behavior in Human Populations

Chronotype describes an individual’s biological predisposition for the timing of sleep and wakefulness, often classified as morning, intermediate or evening types. Advances in assessment methods, combining self-report questionnaires, actigraphy and biological markers, have elucidated how circadian preference influences sleep duration, quality and timing across diverse populations. The distribution of chronotypes follows a bell-shaped curve, with extreme early and late types exhibiting heightened vulnerability to misalignment when social schedules conflict with endogenous rhythms. Standardised instruments, such as the Munich Chronotype Questionnaire and dim light melatonin onset, provide quantitative insight into phase of entrainment, while metrics of social jetlag capture discrepancies between internal clocks and societal obligations. Research has linked chronotype to demographic, geographic and lifestyle factors including age, sex, socioeconomic status and evening light exposure. Evening types often experience shorter or fragmented sleep, greater daytime tiredness and elevated risk of mood and metabolic disturbances, whereas morning types tend to align more closely with conventional work and school schedules. The proliferation of non-standard work hours and digital media use has heightened interest in personalised interventions—optimised scheduling, light therapy and public health policies on daylight saving—to enhance synchrony between biological and social clocks and thus improve sleep health worldwide.

Research from Nature Portfolio

Large-scale analysis of a nationally representative Hungarian cohort revealed that self-reported chronotype correlates with demographic variables and health behaviours. Later chronotypes were more prevalent among younger, higher-income urban dwellers and exhibited greater social jetlag. Alcohol consumption, smoking and reduced physical activity emerged as predictors of both delayed phase and social jetlag, while many health outcomes were largely mediated by age and socioeconomic factors. Complementary findings from a Czech population survey using sleep diaries and chronotype questionnaires identified significant geographic gradients in mid-sleep times. Younger adults caring for children showed earlier chronotypes, whereas dog ownership was linked to later timing. In women, higher body mass index correlated with delayed phase and lower protective cholesterol, supporting proposals for adopting year-round standard time to better align social hours with biological rhythms.

Chronotype Assessment and Sleep Behavior in Human Populations publication trend

The graph below shows the total number of articles in chronotype assessment and sleep behavior in human populations across all publications each year (not limited to Nature Index journals).

Technical terms

Chronotype: An individual’s innate preference for the timing of sleep and activity within the 24-hour cycle.

Social jetlag: The misalignment between biological timing and social schedules, measured as the difference between mid-sleep on workdays and free days.

Mid-sleep on free days (MSFsc): The midpoint of sleep on days without scheduled obligations, corrected for sleep debt accumulated during workdays.

Munich Chronotype Questionnaire (MCTQ): A self-report tool that calculates chronotype based on reported sleep timing on work and free days.

Dim light melatonin onset (DLMO): The time in dim light at which melatonin secretion begins, serving as a reliable biological marker of circadian phase.

References

1. Daily rhythms, light exposure and social jetlag correlate with demographic characteristics and health in a nationally representative survey. Scientific Reports (2023).
2. Chronotype assessment via a large scale socio-demographic survey favours yearlong Standard time over Daylight Saving Time in central Europe. Scientific Reports (2020).
3. Late-Night Digital Media Use in Relation to Chronotype, Sleep and Tiredness on School Days in Adolescence. Journal of Youth and Adolescence (2022).
4. Evening-types show highest increase of sleep and mental health problems during the COVID-19 pandemic—multinational study on 19 267 adults. Sleep (2021).
5. Association between the Munich Chronotype Questionnaire and Wrist Actigraphy. Sleep Disorders (2018).
6. Concordance of Chronotype Categorisations Based on Dim Light Melatonin Onset, the Morningness-Eveningness Questionnaire, and the Munich Chronotype Questionnaire. Clocks & Sleep (2021).