Individuals are different 'chronotypes' with early 'larks' and late 'owls' forming the limits of a normal distribution in the population. We recently described that late chronotypes who suffer from a conflict between internal and external time ('social jetlag') suffer from more mental distress and are more likely to smoke than early chronotypes (Wittmann, Dinich, Merrow, and Roenneberg, 2006 . ...

OBJECTIVE The aim of this study was to compare sleep pattern, tiredness sensation and quality of life between different chronotypes in train drivers from a Brazilian transportation company. SUBJECTS AND METHODS Ninety-one train drivers, working a rotary work schedule including night shift, were divided into three groups according to their chronotype (morning types, intermediate or evening typ...

Abstract Introduction Chronotype refers to one’s inclination earlier or later sleeping times. Late chronotype has been linked increased diabetes risk, which may be mediated through adherence unhealthy lifestyle. This study aimed evaluate the interplay among chronotype, lifestyle factors, and risk. Methods In 2009, 63,594 diabetes-free women (mean age=54 yrs) from Nurses’ Health Study II self-re...

OBJECTIVE To examine whether a mismatch between chronotype (i.e., preferred sleep timing) and work schedule is associated with type 2 diabetes risk. RESEARCH DESIGN AND METHODS In the Nurses' Health Study 2, we followed 64,615 women from 2005 to 2011. Newly developed type 2 diabetes was the outcome measure (n = 1,452). A question on diurnal preference ascertained chronotype in 2009; rotating ...

Circadian rhythms in physiology and behavior are modulated by external factors such as light or temperature. We studied whether self-selected office lighting during the habitual waking period had a different impact on alertness, cognitive performance and hormonal secretion in extreme morning and evening chronotypes (N = 32), whose preferred bed- and wake-up times differed by several hours. The ...

Sleep loss and circadian disruption-a state of misalignment between physiological functions and imposed sleep/wake behavior-supposedly play central roles in the etiology of shift work-related pathologies [1-4]. Circadian entrainment is, however, highly individual [5], resulting in different chronotypes [6, 7]. Chronotype in turn modulates the effects of working times: compared to late chronotyp...

a r t i c l e i n f o Keywords: Chronotype Morningness–eveningness Meta-analysis Cognitive ability Academic achievement Grades Prediction Four meta-analyses examined relationships between morningness and cognitive ability (total N = 2177), eveningness and cognitive ability (total N = 1519), morningness and academic achievement (total N = 3220), and eveningness and academic achievement (total N ...

Background: Individual sleep and activity patterns show large variations are interfered considerably by social schedules. Social jetlag (SJL) is the difference between intrinsic circadian rhythm extrinsically enforced sleep-wake cycle. However, little known about variables affecting severity of SJL. Methodology: We evaluated whether sleep- or smartphone-related affected SJL among college studen...

An individual's chronotype reflects how the circadian system embeds itself into the 24-h day with rhythms in physiology, cognition and behavior occurring accordingly earlier or later. In view of an increasing number of people working at unusual times and linked health and safety risks, the wide range in human chronotypes may provide opportunities to allow people to work (and sleep) at times tha...