Human Activity and Rest In Situ

Roenneberg, Till; Keller, Lena; Fischer, Dorothee; Matera, Joana L.; Vetter, Céline; Winnebeck, Eva C.

doi:10.1016/bs.mie.2014.11.028

Cited by 157 publications

(159 citation statements)

References 38 publications

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“…Significantly, we did not find that light intensity was associated with chronotype. Initially, these findings appear to contradict earlier studies where increased light exposure is associated with an earlier chronotype in the general population (Roenneberg and Merrow 2007; Wright et al 2013; Roenneberg et al 2015; Stothard et al 2017). However, our findings are derived exclusively from a university student population aged between 17 and 26 years.…”

Section: Discussionmentioning

confidence: 56%

“…In a sample of approximately 200,000 individuals from primarily Central Europe and North America, spending more time outside was associated with an earlier chronotype (Roenneberg and Merrow 2007; Roenneberg et al 2015). However, when age was taken into consideration, 15–20 year olds did not show a significant correlation between time spent outside and chronotype, and 20–25 year olds had only a weak correlation (Roenneberg et al 2015).…”

Section: Discussionmentioning

confidence: 99%

“…However, when age was taken into consideration, 15–20 year olds did not show a significant correlation between time spent outside and chronotype, and 20–25 year olds had only a weak correlation (Roenneberg et al 2015). Our sample of over 6000 students (17–26 years) falls across these age ranges and also differs from the Roenneberg sample (MCTQ database) in several important aspects.…”

Section: Discussionmentioning

confidence: 99%

“…The findings demonstrated that increased exposure to natural light advanced the circadian phase of all individuals (Wright et al 2013; Stothard et al 2017). Increasing photic zeitgeber strength by spending more time outside has also been correlated with self-reported chronotype: the more time spent outside, the earlier the chronotype (Roenneberg and Merrow 2007; Roenneberg et al 2015). …”

Section: Introductionmentioning

confidence: 99%

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Chronotype and environmental light exposure in a student population

Porcheret

Wald

Fritschi

et al. 2018

Chronobiology International

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In humans and most other species, changes in the intensity and duration of light provide a critical set of signals for the synchronisation of the circadian system to the astronomical day. The timing of activity within the 24 h day defines an individual’s chronotype, i.e. morning, intermediate or evening type. The aim of this study was to investigate the associations between environmental light exposure, due to geographical location, on the chronotype of university students. Over 6 000 university students from cities in the Northern Hemisphere (Oxford, Munich and Groningen) and Southern Hemisphere (Perth, Melbourne and Auckland) completed the Munich ChronoType Questionnaire. In parallel, light measures (daily irradiance, timing of sunrise and sunset) were compiled from satellite or ground stations at each of these locations. Our data shows that later mid-sleep point on free days (corrected for oversleep on weekends MFSsc) is associated with (i) residing further from the equator, (ii) a later sunset, (iii) spending more time outside and (iv) waking from sleep significantly after sunrise. However, surprisingly, MSFsc did not correlate with daily light intensity at the different geographical locations. Although these findings appear to contradict earlier studies suggesting that in the wider population increased light exposure is associated with an earlier chronotype, our findings are derived exclusively from a student population aged between 17 and 26 years. We therefore suggest that the age and occupation of our population increase the likelihood that these individuals will experience relatively little light exposure in the morning whilst encountering more light exposure later in the day, when light has a delaying effect upon the circadian system.

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Section: Discussionmentioning

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chronotype and environmental light exposure in a student population

Porcheret

Wald

Fritschi

et al. 2018

Chronobiology International

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“…Schultage und freie Tage (Roenneberg, Kuehnle, et al, 2007 Randler, 2009;Smith, Reilly, & Midkiff, 1989) oder die Morningness-EveningnessSubskala des School Sleep Habits Survey (Carskadon, Vieira, & Acebo, 1993) (Roenneberg et al, 2015), der Zeitpunkt der abendlichen Melatonin-Ausschüttung (Molina & Burgess, 2011) und seltener auch der morgendliche Peak der Cortisol-Ausschüttung (Clow, Hucklebridge, Stalder, Evans, & Thorn, 2010). Studien zur Validierung des MEQ zeigten, dass der Peak der Körperkerntemperatur (Bailey & Heitkemper, 2001;Griefahn, Künemund, Bröde, & Mehnert, 2001;Horne & Ostberg, 1976;Ishihara & Miyasita, 1987), der Cortisol-Ausschüttung (Bailey & Heitkemper, 2001) als auch der Zeitpunkt der abendlichen Melatonin-Ausschüttung (Griefahn et al, 2001) (Murray & Lopez, 1996) und Jugendliche besonders späte Chronotypen sind (Roenneberg et al, 2004 Typische Symptome der Depression wie Interessensverlust und Antriebslosigkeit gehen häufig mit sozialem Rückzug einher (Gotlib, 1992;Hagerty, Williams, Coyne, & Early, 1996).…”

Section: Messung Des Chronotypsunclassified

Chronotyp und Depression bei Jugendlichen – ein Review

Keller

Zöschg

Grünewald

et al. 2016

Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapi

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Zusammenfassung. Depressive Erkrankungen gehen mit vielen Symptomen einher, die in Bezug zu einer tageszeitlichen Rhythmik und dem Schlafverhalten stehen. Die vielfältigen Zusammenhänge zwischen Schlaf, Depression und Tagesrhythmik sind nicht eindeutig geklärt. In den Forschungsarbeiten der letzten Jahre kommt dem Chronotyp eine besondere Bedeutung zu. Als biologisches Maß der inneren Uhr kann der Chronotyp – basierend auf Schlafzeiten – mit dem Munich ChronoType Questionnaire (MCTQ) bestimmt werden, als subjektive Präferenz für bestimmte Tageszeiten wird er mit dem Morningness-Eveningness-Questionnaire (MEQ) erfasst. Durch eine systematische Literaturrecherche konnten Studien identifiziert werden, die überwiegend einen Zusammenhang zwischen einem späten Chronotyp und depressiven Symptomen und depressiven Störungen zeigen. Dies ist besonders für Jugendliche relevant, da sich der Chronotyp zur Adoleszenz hin stark verändert. Bisher ist nicht geklärt, was am Zusammenhang zwischen Chronotyp und depressiver Störung Ursache und Wirkung ist und welche Faktoren als Moderator oder Mediator fungieren. Möglicherweise ist der Zusammenhang bidirektional: Einerseits ziehen sich Patienten mit depressiven Störungen häufig zurück und sind weniger Tageslicht ausgesetzt, was ihren Chronotyp später werden lässt. Andererseits führt eine Diskrepanz von Innenzeit (festgelegt durch die innere Uhr) und Außenzeit (z. B. durch Schul- und Arbeitszeiten) zu Problemen wie einer verringerten Schlafqualität und schlechteren Schulnoten, die wiederum im Zusammenhang mit Depressivität stehen können.

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Screen Use at Bedtime and Sleep Duration and Quality Among Youths

Brosnan,

Haszard,

Meredith-Jones

et al. 2024

JAMA Pediatr

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ImportanceAlthough questionnaire-based cross-sectional research suggests that screen time before bed correlates with poor sleep, self-reported data seem unlikely to capture the complexity of modern screen use, requiring objective night-by-night measures to advance this field.ObjectiveTo examine whether evening screen time is associated with sleep duration and quality that night in youths.Design, Setting, and ParticipantsThis repeated-measures cohort study was performed from March to December 2021 in participant homes in Dunedin, New Zealand. Participants included healthy youths aged 11 to 14.9 years. Data were analyzed from October to November 2023.ExposureObjectively measured screen time, captured using wearable or stationary video cameras from 2 hours before bedtime until the first time the youth attempted sleep (shut-eye time) over 4 nonconsecutive nights. Video data were coded using a reliable protocol (κ = 0.92) to quantify device (8 options [eg, smartphone]) and activity (10 options [eg, social media]) type.Main Outcomes and MeasuresSleep duration and quality were measured objectively via wrist-worn accelerometers. The association of screen use with sleep measures was analyzed on a night-by-night basis using mixed-effects regression models including participant as a random effect and adjusted for weekends.ResultsOf the 79 participants (47 [59.5%] male; mean [SD] age, 12.9 [1.1] years), all but 1 had screen time before bed. Screen use in the 2 hours before bed had no association with most measures of sleep health that night (eg, mean difference in total sleep time, 0 minutes [95% CI, –3 to 20 minutes] for every 10 minutes more total screen time). All types of screen time were associated with delayed sleep onset but particularly interactive screen use (mean difference, 10 minutes; 95% CI, 4 to 16 minutes for every additional 10 minutes of interactive screen time). Every 10 minutes of additional screen time in bed was associated with shorter total sleep time (mean difference, –3 minutes; 95% CI, –6 to –1 minute). The mean difference in total sleep time was −9 minutes (95% CI, −16 to −2 minutes) for every 10 minutes of interactive screen use and −4 minutes (95% CI, −7 to 0 minutes) for passive screen use. In particular, gaming (mean difference, –17 minutes; 95% CI, –28 to –7 minutes for every 10 minutes of gaming) and multitasking (mean difference, −35 minutes; 95% CI, –67 to –4 minutes on nights with vs without multitasking) were associated with less total sleep time.Conclusions and RelevanceIn this repeated-measures cohort study, use of an objective method showed that screen time once in bed was associated with impairment of sleep, especially when screen time was interactive or involved multitasking. These findings suggest that current sleep hygiene recommendations to restrict all screen time before bed seem neither achievable nor appropriate.

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Human Activity and Rest In Situ

Cited by 157 publications

References 38 publications

Chronotype and environmental light exposure in a student population

Chronotype and environmental light exposure in a student population

Chronotyp und Depression bei Jugendlichen – ein Review

Screen Use at Bedtime and Sleep Duration and Quality Among Youths

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