Are you a Lark or an Owl?

Understanding whether you are a Lark or an Owl can help you manage sleep disturbances fatigue, health and performance linked to shift work. 

Understanding what natural chronotype you are can help to lessen the effects of late or morning shift work.

Compared to late chronotypes, earlier ones (larks) sleep worse and shorter and show higher levels of circadian misalignment during night shifts, while late types (Owls) experience more sleep and circadian disruption than early types when working morning shifts. [1]

Intermediate chronotypes, representing 30-60% of people, are more adaptable than Larks or Owls and can adjust to shift work. They lack Owls’ night shift advantage, but their flexibility helps minimize sleep problems with rotating schedules. [2]

Shift Schedules for Larks and Owls

Vetter et al. (2015) found that shift schedules customised to individual chronotypes, rather than a uniform approach, can improve sleep duration and quality, reduce social jetlag, and boost health and job satisfaction. [3-4]

Therefore, knowing your chronotype and following schedules that align with it may improve circadian system function, helping to promote restorative sleep and better health outcomes than those experienced by people working shifts outside of their natural biological rhythms. [5]

It is worth knowing that our chronotype, or sleep-wake preference, shifts later in the day during adolescence, peaking around age 20, then gradually moves earlier throughout adulthood, with notable changes between ages 15–25 and after 40. [6] 

Indeed, as we get older, our sleep becomes lighter, shorter, and more fragmented due to shifts in our circadian rhythm and sleep structure. Therefore, aligning shift work with our natural biological rhythms becomes more essential for safety and health. [7]

Which Chronotype are you?

To help assess your own chronotype, The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) is a validated tool for assessing the typology in shift workers. The Munich Chronotype Questionnaire (MCTQShift) is also recommended to capture variations between workdays and days off.

Cognitive Behaviour Therapy

Cognitive Behavioural Therapy for Insomnia (CBT-I) is widely recognised as the "gold standard" first-line treatment for chronic insomnia, as recommended by leading medical bodies such as the American College of Physicians. This structured, non-pharmacological therapy works by targeting and changing problematic behaviours and thoughts related to sleep. Notably, CBT-I has demonstrated a 70–80% success rate in improving sleep, according to clinical studies published by the American College of Physicians, which lends strong credibility to its effectiveness.

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References

[1] Science Direct. 2015. Aligning Work and Circadian Time in Shift Workers Improves Sleep and Reduces Circadian Disruption. https://www.sciencedirect.com/science/article/pii/S0960982215001281#:~:text=Highlights,working%20morning%20shifts%20%5B8%5D.

[2] National Library of Medicine. 2024. Chronotype in relation to shift work: A cohort study among 37,731 female nurses. https://pmc.ncbi.nlm.nih.gov/articles/PMC11911045/#:~:text=Associations%20between%20chronotype%20and%20shift,consider%20chronotype%20as%20effect%E2%80%90modifier.

[3] Science Direct. 2015. Aligning Work and Circadian Time in Shift Workers Improves Sleep and Reduces Circadian Disruption. https://www.sciencedirect.com/science/article/pii/S0960982215001281#:~:text=Highlights,shift%20schedule%20in%20a%20factory.

[4] The BMJ. 2018. Optimising sleep for night shifts. https://www.bmj.com/content/360/bmj.j5637/rr#:~:text=It%20has%20been%20shown%20that,health%20challenge%20for%20different%20people.

[5] Frontiers. 2020. The Future of Shift Work: Circadian Biology Meets Personalised Medicine and Behavioural Science. https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2020.00116/full

[6] Scientific Reports. 2017. From Lark to Owl: developmental changes in morningness-eveningness from new-borns to early adulthood. https://www.nature.com/articles/srep45874#:~:text=Roenneberg%20et%20al.-,2,5%E2%80%9370%20years14).

[7] National Institute on Aging. 2025. Sleep and Older Adults. Sleep and Older Adults | National Institute on Aging.