Chronobiology of Circadian Preference

Chronobiology of circadian preference explores how intrinsic biological clocks govern individual differences in the timing of sleep, wakefulness and peak activity. These preferences, commonly described as chronotypes, range from morning types (‘larks’) to evening types (‘owls’), with intermediate forms in between. Underlying these variations are endogenous circadian rhythms synchronised by environmental cues such as light and temperature. Across the lifespan, chronotype undergoes systematic changes, shifting towards eveningness during adolescence and gradually reverting towards morningness with advancing age. Individual chronotype interacts with social schedules, affecting sleep duration, daytime alertness and performance on cognitive tasks. Recent advances have focused on the genetic, hormonal and environmental determinants of circadian preference, its impact on health outcomes and the potential for personalised interventions that align societal demands with biological timing.

Research from Nature Portfolio

Recent studies have mapped developmental trajectories of circadian preference in very large cross-sectional cohorts, revealing that individuals exhibit strong morningness in infancy, progressively shift towards eveningness in adolescence—with a peak delay around 16–17 years—and then stabilise in early adulthood. Sex differences emerge during puberty, with girls tending to revert towards morningness slightly earlier than boys.

In parallel, systematic analyses of global datasets have demonstrated that geographical factors modulate population-level chronotype. Later sunset times and longer photoperiods at higher latitudes are associated with a greater prevalence of evening orientation, indicating that environmental light cues play a decisive role in shaping circadian preference alongside internal timekeeping mechanisms.

Chronobiology of Circadian Preference publication trend

The graph below shows the total number of articles in chronobiology of circadian preference across all publications each year (not limited to Nature Index journals).

Technical terms

Chronobiology: The scientific study of biological rhythms and their adaptation to periodic environmental changes.

Circadian rhythm: An approximately 24-hour cycle in physiological or behavioural processes driven by an internal clock.

Chronotype: An individual’s predisposition toward earlier or later timing of sleep and wakefulness within the circadian cycle.

Actigraphy: The continuous monitoring of movement, typically via a wrist-worn device, used to infer sleep–wake patterns.

Synchrony effect: Improved cognitive or physical performance when tasks are conducted at an individual’s preferred time of day.

References

1. From Lark to Owl: developmental changes in morningness-eveningness from new-borns to early adulthood. Scientific Reports (2017).
2. Chronotype ontogeny related to gender. Brazilian Journal of Medical and Biological Research (2014).
3. Latitude affects Morningness-Eveningness: evidence for the environment hypothesis based on a systematic review. Scientific Reports (2017).
4. External validity of the reduced Morningness–Eveningness Questionnaire for Children and Adolescents: an actigraphic study. Journal of Sleep Research (2023).
5. Chronotype, Time of Day, and Performance on Intelligence Tests in the School Setting. Journal of Intelligence (2023).