The chronotype is a characteristic manifestation of the inner clock that regulates many physiological and biochemical processes as well as certain cyclic behaviors of a human. Primarily, it is set by an individual genetic disposition. The chronotypes range between extreme larks or extreme owls.
Nowadays, with regard to social times most people rather are owls. This is especially due to the fact that many people very rarely see any daylight. The fewer light the later the inner clock of most people. But since the chronotype also depends on the age, most teenagers are extreme owls.
Conclusion: The later the chronotype the bigger the problems to stick to social schedules. Out of this reason, owls show the biggest difference between their time to go to bed on work-nights and weekends (social jetlag).
Professor Till Roenneberg and his team from the Center of Chronobiology at the University of Munich (LMU) conducted a study and evaluated the information of more than 500 volunteer participants. In the “Munich ChronoType Questionnaire (MCTQ)”, developed by Roenneberg and his team, they had to answer questions concerning their chronotype, well-being as well as consumption of nicotine and alcohol. Amongst other things, they had been questioned about their actual times of sleeping and wakefulness, differentiated for work days and days off, which lead to determination of their chronotype. Furthermore, questions concerning sleeping quality, present and past psychological well-being as well as consumption of caffeine, nicotine and alcohol and similar substances had to be answered. “Based on the answers we were able to explore a connection between social jetlag, sleeping quality, psychologic well-being and consumption of stimulating substances”, so Roenneberg. “We revealed that the conflict of biological clock and social times is leading to a chronical form of jetlag.” Most owls not only accumulate a sleep debt during the week but report more frequent about poorer sleeping quality and daytime tiredness.
“The more severe the social jetlag the more stimulants are used by the individuals”, reports Roenneberg, “and the more frequent they smoke.” As it shows, the latter is a particularly striking connection. “Alcohol- and especially nicotine-consumption often point to difficulties in coping with social demands. This led us to the hypothesis that sleeping problems and nicotine consumption especially occur when the inner sleep-wake-rhythm is not in accordance with the social schedule”, so Roenneberg. Amongst shift workers there are significantly more smokers. The strong correlation of social jetlag and nicotine is especially interesting, because often adolescents start smoking – a time in our lives where our social jetlag is especially pronounced. “Adolescents are shift workers. Their inner clock is giving sleeping times between 2.00 and 10.00 a.m. and they have to get up at 6.00 a.m. Their “inner midnight””, so Roenneberg.
But this is only one possible consequence that might have an effect on the whole life of people concerned. It also is a known fact that students (owls) are not doing that well at school – and this might be connected with their chronical lack of sleep and the lack of sleeping quality. In the long run this limitation might hinder performance for life.
Conclusion: For adolescents and young adults it would be profitable to have the chance to take their inner clock into consideration. An adaption of the school starting times would be necessary. The social jetlag and its harmful effects could be avoided by changes in the social organization.
Receive further information in our sleep-healthy-guidebook “sleep yourself young, fit and successful”, free of cost.
image source: @SAMINA
This post is also available in / Diesen Beitrag gibt es auch in: German