Morningness-eveningness in a large sample of German adolescents and adults

Abstract

People differ in their sleep-wake behavior. This individual difference is conceptualized in different aspects, such as wake up times, bed times, times of peak performance, as well as in morning affect. A total of 14,987 visitors of an exhibition in the LWL State Museum of Natural History, Münster (Germany), did the survey on chronotype and gave their consent that these data can be used for a scientific study. Age groups were coded into 5-year bins. Mean age (mean ± SD) was 28.2 ± 17.5 years. There were 8075 females (54%) and 6912 males in the sample. The German version of the rMEQ (reduced Morningness-Eveningness-Questionnaire) was used for data collection. The data showed clear age effects. Younger children are more morning oriented and become rapidly evening oriented during puberty, while the more attenuated turn towards morningness occurs from the age of 20 years. Then between the ages 25 to 30 morningness-eveningness remained rather stable. Significant gender differences existed in the reproductive age, i.e., the age groups 20 to 50 (corresponding to the age 16–50 years). In other age groups, no gender differences could be detected. Seasonal effects were also found. Chronotype score was lowest during the summer months (and more evening oriented). Based on the single item analysis of the five questions of the rMEQ, we found age group differences in all items. Gender differences occurred in all items except item 1, which deals with the preferred wake-up time. Men always scored significantly lower (i.e. more evening oriented) than women except in item 2 (tiredness after awakening). Seasonal effects were only significant in item 3, which is related to preferred bed times. People showed a later bed time preference during summer. The classification of chronotypes according to the cut-off scores provided by Adan and Almirall (1991) and by using the 20/80 percentile provided identical cut-off scores (values of 11 and below for evening types and 18 and above for morning types).

From Lark to Owl: developmental changes in morningness-eveningness from new-borns to early adulthood

“…: N = 14,650; from ≈20 to >60 years12; Italy: Tonetti et al . : N = 8,972, 10–87 years13; Germany: Randler et al ., N = 14,987; 5–70 years14). …”

Morningness-eveningness and Fatigue in Adolescence

“…While the progressive tendency toward eveningness as a function of age was confirmed in almost all of the previous studies, findings on sex differences are less consistent (4,(25)(26)(27). A higher eveningness preference is found in adolescent girls, although in some studies, differences in the circadian preferences with regard to sex were not found.…”

“…Dok je progresivna tendencija večernjosti u funkciji dobi potvrđena gotovo u svim dosadašnjim istraživanjima, nalazi o razlikama s obzirom na spol manje su konzistentni (4,(25)(26)(27). Najčešće se veća sklonost večernjosti utvrđuje u adolescentica, premda u nekim istraži-vanjima nisu dobivene razlike u cirkadiurnim preferencijama s obzirom na spol.…”

“…U ovom istraživanju utvrđene su značajne razlike: adolescentice su bile značajno sklonije večernjosti od adolescenata. Dobiveni nalazi najčešće se tumače ranijim početkom puberteta kod djevojčica i njihovim ranijim doživljavanjem bioloških promjena koje sudjeluju u cirkadiurnoj regulaciji (3,6,7,27). Adolescentice općenito radnim danom idu kasnije na spavanje i ustaju ranije, ali to onda nadoknađuju vikendom kada je duže spavanje više u skladu s njihovim cirkadiurnim preferencijama (26).…”

“…U interpretacijama dobivenih razlika najčešće se koriste dva tumačenja: jedno, prema kojem raniji ulazak djevojaka u pubertet realno povećava broj tjelesnih simptoma općenito, pa tako i umora, i drugo, prema kojem djevojke imaju općenito veću interoceptivnu osjetljivost na tjelesne simptome, pa tako i simptome umora. Ovo drugo tumačenje circadian rhythm (3,6,7,27). Adolescent girls have later bedtimes and rise earlier on weekdays, but they have longer sleep lengths on weekends that are in accordance with their circadian preferences (26).…”