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Social jetlag

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Social jetlag, similar to jet lag, is a circadian misalignment. The term “social jetlag” was first coined in 2006 by German scientist Till Roennenberg and colleagues, and they define it as “the discrepancy of work and free days, between social and biological time.”[1] This means that one’s biological clock does not align with their social obligations, whether it be work or otherwise. Since the term's initial coinage, the term has become widely used and understood. According to PubMed, at least 26 articles have been published on social jetlag as of April 2025.[2] Additionally, many papers have since been published exploring how social jetlag specifically affects health outcomes.

How to calculate social jetlag

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Social jetlag is calculated by the difference in the midpoint of sleep on workdays and free days. The midpoint is the halfway point between bedtime and wake time. The larger the difference, the most extreme the jetlag.

Social jeglag = midpoint of sleep on workays — midpoint of sleep on free days.

Discovery

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In the 2006 study from Till Roennenberg and Marc Wittmann,they were credited as being the first people to explore the phenomenon that they termed "social jetlag." Their initial investigations included questionnaires for 501 participants. The participants answered questions relating to their sleep quality, current psychological well-being, retrospective psychological well-being from the past week, and consumption of stimulants (e.g. caffeine or nicotine). Roennenberg and Wittmann's findings interestingly showed a strong positive correlation between late chronotypes and smoking habits, among other stimulants.[1] This means that people with late chronotypes were more likely to take part in stimulant usage. The work of Roenneberg and his lab paved the way for further research on the concept of social jetlag and how the mismatch between social obligations and chronotype can impact ones’ habits and health.

Causes

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Social jetlag arises from a mismatch between an individual's internal biological clock and the external demands of society, particularly work and school obligations. This misalignment is influenced by several interrelated factors:

Chronotype variability

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Chronotype can be defined using actual sleep-wake timing (Munich Chronotype Questionnaire) or an individual’s preference for earlier or later sleep and wake times. Chronotype plays a central role in the development of social jetlag. Evening chronotypes (commonly referred to as “night owls”) are particularly susceptible, as their internal clocks are naturally delayed relative to societal norms. As a result, they often accumulate a significant sleep debt during work or school days, which they attempt to compensate for by sleeping in on free days, further exacerbating circadian misalignment.[1] Population-level data suggest that over 70% of people experience at least one hour of social jetlag per week, with evening chronotypes reporting the highest average misalignment.[3]

Light exposure and technology use

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Exposure to artificial light, particularly blue light from electronic devices, in the evening hours can suppress melatonin production and delay circadian phase. This delay may conflict with early morning obligations, leading to later bedtimes and greater weekday misalignment. On the other hand, insufficient morning light exposure can fail to advance the circadian clock, which reinforces delayed sleep phases.[4][5][6] Some research also suggests evening light may blunt circadian amplitude, potentially making weekday realignment more difficult, though the specific mechanisms aren't fully clear.[7]

Work and school schedules

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Fixed early-morning start times for work and education are among the most significant external pressures leading to social jetlag. These schedules are typically optimized for morning chronotypes, forcing individuals with later circadian preferences to truncate their sleep duration or shift their natural sleep phase, leading to chronic sleep misalignment.[1] This effect is most pronounced in adolescents and young adults, whose circadian systems tend to shift later during puberty, creating a mismatch between biological and institutional timing.[1][8]

Use of alarm clocks

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Alarm clocks interrupt natural sleep timing by enforcing externally determined wake times. Individuals who consistently wake to alarms are more likely to have a discrepancy between their biological and social clocks. However, alarm use is more likely a consequence of misalignment than a cause, as people with later chronotypes may rely on alarms because their natural wake time is out of sync with societal schedules. This regular artificial truncation of sleep contributes to the accumulation of social jetlag across the week. Studies have shown that the need for an alarm clock correlates with greater social jetlag severity, serving as a proxy for insufficient alignment between internal and external timing cues.[1][9]

Social and recreational activities

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Evening social activities and screen time can push bedtime later, particularly among adolescents and young adults. These behavioral patterns, when combined with rigid weekday wake times, contribute to a widened gap between sleep timing on workdays and free days, which is a defining feature of social jetlag. "Catch-up sleep" on weekends, while often used to recover sleep debt, may result in greater sleep timing variability across the week. This irregularity, rather than catch-up sleep itself, is what contributes to circadian disruption.[1][3]

Measurement and assessment

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Social jetlag is typically assessed through subjective questionnaires and objective physiological measurements.[3]

Munich Chronotype Questionnaire

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The Munich Chronotype Questionnaire is a widely used tool that assesses habitual sleep-wake timing separately for workdays and free days. Chronotype is calculated based on the midpoint of sleep on free days, adjusted for oversleep to account for weekday sleep debt.[3] Social jetlag is quantified as the absolute difference between mid-sleep on free days and mid-sleep on workdays, providing a measure of circadian misalignment.[3][1]

However, a limitation of the questionnaire is its reliance on structured work schedules, restricting its applicability in populations with flexible schedules or culturally relaxed attitudes towards work timing.[10] Additionally, the MCTQ simplifies sleep compensation by focusing primarily on circadian influences, even though sleep timing is also significantly regulated by homeostatic mechanisms.[10]

Actigraphy

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Actigraphy objectively measures sleep-wake cycles through wrist-worn accelerometers recording wrist movements, analyzed with specialized software algorithms. This method estimates total sleep time (TST), sleep efficiency, and wake after sleep onset, though its accuracy for sleep-onset latency (SOL) and daytime sleep estimation is limited.[11] Actigraphy-derived Mid Sleep Phase (MSP) on workdays and free days is used to calculate social jetlag, defined as the difference between these values. Studies employing actigraphy have linked higher social jetlag with impaired cognitive and motor functions.[12]

Theoretical and psychological considerations

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The dual-oscillator circadian modeltheorizes two coupled oscillators—morning and evening—responding differently to environmental light cues. This model elucidates circadian misalignment phenomena, including phase shifts and rhythm splitting under constant conditions, and provides insights into biological entrainment variability.[13]

The interaction of these oscillators can explain complex circadian phenomena such as internal desynchronization and rhythm splitting, which occur when environmental signals are inconsistent or absent, leading each oscillator to run independently and display distinct rhythmic patterns.[13] Coupling within these oscillators contributes to the robustness and stability of circadian timing, allowing organisms to adapt flexibly to changing environmental conditions.[14] Thus, Pittendrigh’s dual-oscillator model provides a theoretical framework to understand circadian misalignment phenomena, including social jetlag, by elucidating how variability in internal oscillator coupling influences individual responses to environmental cues.[13]

Additionally, psychological factors, such as expectations about jet lag severity, significantly influence symptom intensity. Research has shown that expectations prior to travel predict jet lag symptoms more accurately than traditional circadian metrics, emphasizing the importance of integrating psychological assessments in social jetlag evaluation.[12]

Health implications

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Social jet lag has been linked to obesity, body mass index, and waist circumference.[15] Similarly, studies have associated social jet lag with an inability to follow healthy diets, but a direct link establishing causality has not yet been established.[15] Social jet lag has also been linked to metabolic disorders such as type 2 diabetes and insulin resistance, with several studies reporting associations between social jet lag and impaired glucose metabolism, though variations in measurement methods and lack of sleep debt correction limit the strength of these conclusions.[16] Further longitudinal and experimental studies are needed to determine whether social jet lag directly contributes to these health issues or if the observed relationships are confounded by other lifestyle or environmental factors.

Psychiatric effects

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Social jet lag has also been associated with adverse mental health outcomes, including mood disorders like major depressive disorder and bipolar disorder.[17][7] Large-scale and cross-sectional studies have found a positive correlation between social jet lag and the severity of depressive symptoms.[9] However, findings remain inconsistent, as some studies, including those involving patients with depression have not observed significant differences compared to healthy controls. Research on other psychiatric conditions, such as anxiety and ADHD, has yielded mixed results,[18][19][20] underscoring the need for further studies using objective and standardized methodologies.

Reduced performance

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Reduced sleep duration and poor sleep quality have also been connected with social jet lag, particularly among evening chronotypes.[1] A recent study found that individuals with high social jet lag exhibited lower heart rate variability, a marker of poor sleep quality.[4] This is particularly evident in shift workers, who often experience up to three hours of social jet lag due to irregular schedules.[21] This diminished sleep quality may impair the restorative function of sleep, leading to increased fatigue, reduced alertness, and poorer academic or workplace performance.[8][22] Similarly, social jetlag has been associated with cardiovascular disease risk like higher triglyceride levels.[23][2]

Mitigation strategies

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Light interventions

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Entrainment by light exposure, specifically the duration, intensity, time of day, and wavelength can impact circadian rhythms and exacerbate or alleviate social jetlag.[5] As such, light interventions are generally the first step in circadian treatment. Specifically, blue light is known to induce melatonin suppression that results in later bedtimes[6] which can exacerbate social jetlag. Reducing blue light at the end of the day can help increase melatonin excretion earlier in the night, leading to earlier bedtimes.[5] Blue light reduction means limiting electronic device use (ie. phones, TVs, computers, etc.) or wearing color-tinted (normally orange) glasses.[24] While increasing light exposure earlier in the morning can help elevate mood and circadian entrainment,[25] there are no explicit benefits in solving social jetlag, but can be a point of future study.[5] While there are general benefits of reducing blue light exposure during bedtime, there is little known about the effectiveness of light interventions. There are too many factors that cannot be controlled, including timing of light exposure, ambient lighting, and individual variability.[26] There are no other current mitigation strategies but further look into interventions of travel jet lag, such as melatonin administration and pharmacotherapy are being examined.[27]

Reducing the difference between social and biological clock

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Another possibility to limit social jetlag includes reducing the difference between the social clock on free days and the enforced schedule on work days. A study shows that later school start times for adolescent children can help students with late chronotypes get sufficient sleep.[28] In fact, younger adults generally prefer waking up later as a whole, so shifting school days can help minimize the effects of social jetlag.[28]

Limitations

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  • Social jetlag is only one measure of chronodisruption. Other forms include shift work or other diseases that can affect circadian rhythms.
  • There is lack of research on the biological mechanisms that underly social jetlag.[29]
  • Social jetlag is only diagnosed through subjective surveys such as the Munich Chronotype Questionnaire which makes diagnosis less accurate and does not account for variability between work and free days.[29]
  • While social jetlag is correlated to negative health outcomes, there is no research on the direct cause of disease.[29]

See also

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References

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  1. ^ a b c d e f g h i Wittmann M, Dinich J, Merrow M, Roenneberg T. Social jetlag: misalignment of biological and social time. Chronobiol Int. 2006;23(1-2):497-509. doi: 10.1080/07420520500545979. PMID 16687322.
  2. ^ a b Caliandro, Rocco; Streng, Astrid A.; van Kerkhof, Linda W. M.; van der Horst, Gijsbertus T. J.; Chaves, Inês (2021-12-18). "Social Jetlag and Related Risks for Human Health: A Timely Review". Nutrients. 13 (12): 4543. doi:10.3390/nu13124543. ISSN 2072-6643. PMC 8707256. PMID 34960096.
  3. ^ a b c d e Roenneberg, Till; Allebrandt, Karla V.; Merrow, Martha; Vetter, Céline (2012-05-01). "Social Jetlag and Obesity". Current Biology. 22 (10): 939–943. Bibcode:2012CBio...22..939R. doi:10.1016/j.cub.2012.03.038. PMID 22578422.
  4. ^ a b Sűdy, Ágnes Réka; Ella, Krisztina; Bódizs, Róbert; Káldi, Krisztina (2019). "Association of Social Jetlag With Sleep Quality and Autonomic Cardiac Control During Sleep in Young Healthy Men". Frontiers in Neuroscience. 13: 950. doi:10.3389/fnins.2019.00950. ISSN 1662-4548. PMC 6742749. PMID 31555086.
  5. ^ a b c d Zerbini, Giulia; Kantermann, Thomas; Merrow, Martha (2020). "Strategies to decrease social jetlag: Reducing evening blue light advances sleep and melatonin". European Journal of Neuroscience. 51 (12): 2355–2366. doi:10.1111/ejn.14293. ISSN 1460-9568. PMID 30506899.
  6. ^ a b Wahl, Siegfried; Engelhardt, Moritz; Schaupp, Patrick; Lappe, Christian; Ivanov, Iliya V. (2019-12-01). "The inner clock—Blue light sets the human rhythm". Journal of Biophotonics. 12 (12): e201900102. doi:10.1002/jbio.201900102. ISSN 1864-063X. PMC 7065627. PMID 31433569.
  7. ^ a b Chung, Jae Kyung; Lee, Kyu Young; Kim, Se Hyun; Kim, Eui-Joong; Jeong, Seong Hoon; Jung, Hee Yeon; Choi, Jung-Eun; Ahn, Yong Min; Kim, Yong Sik; Joo, Eun-Jeong (2012-08-01). "Circadian Rhythm Characteristics in Mood Disorders: Comparison among Bipolar I Disorder, Bipolar II Disorder and Recurrent Major Depressive Disorder". Clinical Psychopharmacology and Neuroscience. 10 (2): 110–116. doi:10.9758/cpn.2012.10.2.110. ISSN 1738-1088. PMC 3569143. PMID 23430379.
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  9. ^ a b Levandovski, Rosa; Dantas, Giovana; Fernandes, Luciana Carvalho; Caumo, Wolnei; Torres, Iraci; Roenneberg, Till; Hidalgo, Maria Paz Loayza; Allebrandt, Karla Viviani (2011-11-01). "Depression scores associate with chronotype and social jetlag in a rural population". Chronobiology International. 28 (9): 771–778. doi:10.3109/07420528.2011.602445. ISSN 1525-6073. PMID 21895489.
  10. ^ a b Roenneberg, Till; Pilz, Luísa K.; Zerbini, Giulia; Winnebeck, Eva C. (2019-07-12). "Chronotype and Social Jetlag: A (Self-) Critical Review". Biology. 8 (3): 54. doi:10.3390/biology8030054. ISSN 2079-7737. PMC 6784249. PMID 31336976.
  11. ^ Martin, Jennifer L.; Hakim, Alex D. (2011-06-01). "Wrist Actigraphy". Chest. 139 (6): 1514–1527. doi:10.1378/chest.10-1872. PMC 3109647. PMID 21652563.
  12. ^ a b Umemura, Guilherme Silva; Pinho, João Pedro; da Silva Brandão Gonçalves, Bruno; Furtado, Fabianne; Forner-Cordero, Arturo (2018-06-20). "Social jetlag impairs balance control". Scientific Reports. 8 (1): 9406. Bibcode:2018NatSR...8.9406U. doi:10.1038/s41598-018-27730-5. ISSN 2045-2322. PMC 6010412. PMID 29925863.
  13. ^ a b c Pittendrigh, Colin S.; Daan, Serge (1976-10-01). "A functional analysis of circadian pacemakers in nocturnal rodents: V. Pacemaker structure: A clock for all seasons". Journal of Comparative Physiology A. 106 (3): 333–355. doi:10.1007/BF01417860. ISSN 0340-7594.
  14. ^ Mohawk, Jennifer A.; Green, Carla B.; Takahashi, Joseph S. (2012-07-21). "Central and Peripheral Circadian Clocks in Mammals". Annual Review of Neuroscience. 35 (1): 445–462. doi:10.1146/annurev-neuro-060909-153128. ISSN 0147-006X. PMC 3710582. PMID 22483041.
  15. ^ a b Arab, Arman; Karimi, Elham; Garaulet, Marta; Scheer, Frank A. J. L. (2024-03-01). "Social jetlag and obesity: A systematic review and meta-analysis". Obesity Reviews. 25 (3): e13664. doi:10.1111/obr.13664. ISSN 1467-789X. PMID 38072635 – via PubMed.
  16. ^ Koopman, Anitra D. M.; Rauh, Simone P.; van 't Riet, Esther; Groeneveld, Lenka; van der Heijden, Amber A.; Elders, Petra J.; Dekker, Jacqueline M.; Nijpels, Giel; Beulens, Joline W.; Rutters, Femke (2017-08-01). "The Association between Social Jetlag, the Metabolic Syndrome, and Type 2 Diabetes Mellitus in the General Population: The New Hoorn Study". Journal of Biological Rhythms. 32 (4): 359–368. doi:10.1177/0748730417713572. ISSN 1552-4531. PMC 5564947. PMID 28631524.
  17. ^ Ahn, Yong Min; Chang, Jaeseung; Joo, Yeon Ho; Kim, Seong Chan; Lee, Kyu Young; Kim, Yong Sik (2008-03-01). "Chronotype distribution in bipolar I disorder and schizophrenia in a Korean sample". Bipolar Disorders. 10 (2): 271–275. doi:10.1111/j.1399-5618.2007.00573.x. ISSN 1398-5647. PMID 18271906.
  18. ^ Baek, Seong-Uk; Lee, Yu-Min; Won, Jong-Uk; Yoon, Jin-Ha (2025-02-01). "Association between social jetlag and anxiety symptoms: Findings from a nationally representative sample of the Korean working population". Sleep Medicine. 126: 300–306. doi:10.1016/j.sleep.2024.12.029. ISSN 1878-5506. PMID 39740475.
  19. ^ Mathew, Gina Marie; Li, Xian; Hale, Lauren; Chang, Anne-Marie (2019-04-01). "Sleep duration and social jetlag are independently associated with anxious symptoms in adolescents". Chronobiology International. 36 (4): 461–469. doi:10.1080/07420528.2018.1509079. ISSN 1525-6073. PMC 6397070. PMID 30786775.
  20. ^ Qu, Xueqi; Kalb, Luther G.; Holingue, Calliope; Rojo-Wissar, Darlynn M.; Pritchard, Alison E.; Spira, Adam P.; Volk, Heather E.; Jacobson, Lisa A. (2024-01-01). "Association of Time in Bed, Social Jetlag, and Sleep Disturbances With Cognitive Performance in Children With ADHD". Journal of Attention Disorders. 28 (1): 99–108. doi:10.1177/10870547231204010. ISSN 1557-1246. PMC 11166002. PMID 37864347.
  21. ^ Boivin, Diane B.; Boudreau, Philippe; Kosmadopoulos, Anastasi (2022-02-01). "Disturbance of the Circadian System in Shift Work and Its Health Impact". Journal of Biological Rhythms. 37 (1): 3–28. doi:10.1177/07487304211064218. ISSN 0748-7304. PMC 8832572. PMID 34969316.
  22. ^ Moon, H. J.; Yoo, S.; Cho, Y. W. (2017-10-15). "The effect of chronotype and social jetlag on sleep, mental health, quality of life, and academic performance of medical students". Journal of the Neurological Sciences. 381: 296–297. doi:10.1016/j.jns.2017.08.841. ISSN 0022-510X. PMID 28991701.
  23. ^ Belloir, Joseph; Makarem, Nour; Shechter, Ari (2022-12-01). "Sleep and Circadian Disturbance in Cardiovascular Risk". Current Cardiology Reports. 24 (12): 2097–2107. doi:10.1007/s11886-022-01816-z. ISSN 1523-3782. PMC 9811983. PMID 36327055.
  24. ^ Shechter, Ari; Quispe, Kristal A; Mizhquiri Barbecho, Jennifer S; Slater, Cody; Falzon, Louise (2020-03-01). "Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep: A systematic review and meta-analysis". SLEEP Advances. 1 (1): zpaa002. doi:10.1093/sleepadvances/zpaa002. ISSN 2632-5012. PMC 10127364. PMID 37192881.
  25. ^ Clodoré, M.; Foret, J.; Benoit, O.; Touitou, Y.; Aguirre, A.; Bouard, G.; Touitou, C. (January 1990). "Psychophysiological effects of early morning bright light exposure in young adults". Psychoneuroendocrinology. 15 (3): 193–205. doi:10.1016/0306-4530(90)90030-D. PMID 2255748.
  26. ^ Bin, Yu Sun; Postnova, Svetlana; Cistulli, Peter A. (2019-02-01). "What works for jetlag? A systematic review of non-pharmacological interventions". Sleep Medicine Reviews. 43: 47–59. doi:10.1016/j.smrv.2018.09.005. ISSN 1087-0792. PMID 30529430.
  27. ^ Arendt, Josephine (2018-09-01). "Approaches to the Pharmacological Management of Jet Lag". Drugs. 78 (14): 1419–1431. doi:10.1007/s40265-018-0973-8. ISSN 0012-6667. PMC 6182450. PMID 30167980.
  28. ^ a b Au, Rhoda; Carskadon, Mary; Millman, Richard; Wolfson, Amy; Braverman, Paula K.; Adelman, William P.; Breuner, Cora C.; Levine, David A.; Marcell, Arik V.; Murray, Pamela J.; O’Brien, Rebecca F.; Devore, Cynthia D. (2014-09-01). "School Start Times for Adolescents". Pediatrics. 134 (3): 642–649. doi:10.1542/peds.2014-1697. ISSN 0031-4005. PMC 8194457. PMID 25156998.
  29. ^ a b c Vetter, Céline (January 2020). "Circadian disruption: What do we actually mean?". European Journal of Neuroscience. 51 (1): 531–550. doi:10.1111/ejn.14255. ISSN 0953-816X. PMC 6504624. PMID 30402904.
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