Not to be confused with Chronotope or Chronotrope.
"Diurnal variation" redirects here. For the temperature range between daily highs and lows, see Diurnal temperature variation.
A chronotype is the behavioral manifestation of underlying circadian rhythm's myriad of physical processes. A person's chronotype is the propensity for the individual to sleep at a particular time during a 24-hour period. Eveningness (delayed sleep period; most active and alert in the evening) and morningness (advanced sleep period; most active and alert in the morning) are the two extremes with most individuals having some flexibility in the timing of their sleep period. However, across development there are changes in the propensity of the sleep period with pre-pubescent children preferring an advanced sleep period, adolescents preferring a delayed sleep period and many elderly preferring an advanced sleep period.
The causes and regulation of chronotypes, including developmental change, individual propensity for a specific chronotype, and flexible versus fixed chronotypes have yet to be determined. However, research is beginning to shed light on these questions, such as the relationship between age and chronotype.[1] There are candidate genes (called CLOCK genes) that exist in most cells in the body and brain, referred to as the circadian system that regulate physiological phenomena (hormone levels, metabolic function, body temperature, cognitive faculties, and sleeping). With the exception of the most extreme and rigid chronotypes, regulation is likely due to gene-environment interactions. Important environmental cues (zeitgebers) include light, feeding, social behavior, and work and school schedules. Additional research has proposed an evolutionary link between chronotype and nighttime vigilance in ancestral societies.[2]
Humans are normally diurnal creatures that are active in the daytime.[citation needed] As with most other diurnal animals, human activity-rest patterns are endogenously regulated by biological clocks with a circadian (~24-hour) period.[citation needed] Chronotypes have also been investigated in other species, such as fruit flies[3] and mice.[4]
Normal variation in chronotype encompasses sleep–wake cycles that are two to three hours later in evening types than morning types.[5] Extremes outside of this range can cause a person difficulty in participating in normal work, school, and social activities. If a person's "lark" or (more commonly) "owl" tendencies are strong and intractable to the point of disallowing normal participation in society, the person is normally considered to have a circadian rhythm sleep disorder.[6]
^Walker RJ, Kribs ZD, Christopher AN, Shewach OR, Wieth MB (2014). "Age, the Big Five, and time-of-day preference: A mediational model". Personality and Individual Differences. 56: 170–174. doi:10.1016/j.paid.2013.09.003. S2CID 18325145.
^Zakharenko LP, Petrovskii DV, Putilov AA (21 June 2018). "Larks, owls, swifts, and woodcocks among fruit flies: differential responses of four heritable chronotypes to long and hot summer days". Nature and Science of Sleep. 10: 181–191. doi:10.2147/NSS.S168905. PMC 6016586. PMID 29950910.
^Refinetti R, Wassmer T, Basu P, Cherukalady R, Pandey VK, Singaravel M, et al. (July 2016). "Variability of behavioral chronotypes of 16 mammalian species under controlled conditions". Physiology & Behavior. 161: 53–59. doi:10.1016/j.physbeh.2016.04.019. PMID 27090227.
^Lack L, Bailey M, Lovato N, Wright H (2009). "Chronotype differences in circadian rhythms of temperature, melatonin, and sleepiness as measured in a modified constant routine protocol". Nature and Science of Sleep. 1: 1–8. doi:10.2147/nss.s6234. PMC 3630920. PMID 23616692.
^The international classification of sleep disorders(PDF) (revised: diagnostic and coding manual ed.). Rochester, MN: American Sleep Disorders Association. 2001. ISBN 0-9657220-1-5. Archived from the original (PDF) on 27 September 2007.
A chronotype is the behavioral manifestation of underlying circadian rhythm's myriad of physical processes. A person's chronotype is the propensity for...
The Munich Chronotype Questionnaire (MCTQ) was created in 1976 by Till Roenneberg and Martha Merrow at Ludwig-Maximilians University (LMU) Munich. The...
optimal for chronotype (i.e. evening for evening chronotypes vs. morning for morning chronotypes) and once at a time that is suboptimal for chronotype (i.e....
activities at dusk or in the evening, which is consistent with the evening chronotype. People experiencing diurnal mood variation consistently prefer later...
impact of light on human circadian rhythms, focusing on aspects such as chronotypes and social jet lag in relation to health benefits. Roenneberg was born...
Bedding Bedroom Bedtime Procrastination Story Biphasic and polyphasic sleep Chronotype Comfort object Dream diary Microsleep Nap Nightwear Power nap Second wind...
traditionally use the terms morningness and eveningness for the two chronotypes or diurnality and nocturnality in animal behavior. In several countries...
Rivero, M. S.; Simonelli, G.; Vigo, D. E.; Plano, S. A. (2023-09-24). "Chronotype delay and sleep disturbances shaped by the Antarctic polar night". Scientific...
Vernalization Fields Behavioural ecology Chronobiology Ethology See also Chronotype Diel vertical migration Light pollution Solunar theory Parts of a day...
diurnal in Wiktionary, the free dictionary. Diurnal cycle Cathemeral Chronotype Crepuscular Crypsis Nocturnality Vinne, Vincent van der; Gorter, Jenke...
and "night owl", are called chronotypes. Genetics and sex have some influence on chronotype, but so do habits. Chronotype is also liable to change over...
respectively). Chronotypes Humans can have a propensity to be morning people or evening people; these behavioral preferences are called chronotypes for which...
IV.4 (1924), pp. 397–410. M. E. Vines, M. E. Vines, "The 'Trial Scene' Chronotype in Mark and the Jewish Novel", in G. van Oyen and T. Shepherd (eds.),...
tides, in which case the interval is closer to 12 hours and 25 minutes. Chronotype Circadian rhythm Diel vertical migration Diurnality Diurnal Climate [de]...
temperatures are taken continuously. Though variation is great among normal chronotypes, the average human adult's temperature reaches its minimum at about 5:00 a...
organisms that are only or primarily active in the evening. Circadian rhythm Chronotype "Aye-Aye Daubentonia madagascariensis". National Geographic. Retrieved...
organisms that are only or primarily active in the evening. Circadian rhythm Chronotype List of nocturnal animals Dunn, J. L. & Alderfer, J. (2006) "Nocturnal...
experience an inability to maintain a consistent internal clock. Extreme chronotypes usually maintain a consistent clock, but find that their natural clock...
function, there is variation in chronotypes, or preferred wake and sleep times, of individuals. Although chronotype varies from individual to individual...
IV.4 (1924), pp. 397–410. M. E. Vines, M. E. Vines, "The 'Trial Scene' Chronotype in Mark and the Jewish Novel", in G. van Oyen and T. Shepherd (eds.),...
the original on April 7, 2023. Retrieved March 31, 2022. The Boston "Chronotype," Oct. 1, 1846 edition "Leo, the Royal cadet [microform]: Cameron, George...
Bedding Bedroom Bedtime Procrastination Story Biphasic and polyphasic sleep Chronotype Comfort object Dream diary Microsleep Nap Nightwear Power nap Second wind...
(2014). "Computer Game Addiction in Adolescents and Its Relationship to Chronotype and Personality". SAGE Open. 4 (1): 215824401351805. doi:10.1177/2158244013518054...
with ADHD. A 2019 study from Boston showed a relationship of evening chronotypes and greater social jet lag with greater body weight / adiposity in adolescent...
be constant across "night owls" and "early birds", or different sleep chronotypes, as revealed by fMRI and graph theory. Studies on rodents show that the...
sleepiness during the day in adolescents aged 11–17 years old. Munich Chronotype Questionnaire (MCTQ): Assesses the timing of sleep. When sleep complaints...
nature completed in 2013 under the report titled "Creatures of the Night: Chronotypes and the Dark Triad Traits" (Peter K. Jonason, Amy Jones, and Minna Lyons...
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