Owls and Larks: Learn more about Chronotypes!
You missed the TUM4Health prevention day on sleep and still want to find out which chronotype you are?
With the help of Reduced Morningness-Eveningness Questionnaires (Adan & Almirall 1991) a sum score can be calculated based on five questions and your preferred sleep type can be determined.
Learn more about your chronotype!
You can find information on typical characteristics of the respective types, helpful tips for everyday life and interesting facts from science here (supplement material is only available in German):
Chronotype - What is it anyway?
Circadian rhythms
are changes in cellular, molecular and biological processes that are repeated approximately every 24 hours. These processes respond primarily to light and darkness and affect most living things, including animals, plants, and microorganisms. The circadian rhythm is driven by a central internal clock (master clock) located in the suprachiasmatic nucleus (SCN) of the hypothalamus above the junction of the optic nerves.
The chronotype is an expression of the circadian rhythm, which is related to sleep patterns, digestion as well as physical activity. While the circadian rhythm is responsible for processes during the day and night, the chronotype determines when these processes take place.
An important difference between the circadian rhythm and the chronotype is how malleable they are. Internal and exogenous components such as environmental stimuli or zeitgebers (such as light and caffeine) can keep the internal clock on track or throw it off track. That's why
the circadian rhythm is malleable to some degree. Our chronotype, on the other hand, is half genetically determined and largely immune to change.
In the course of our lives, there are shifts in the sleep-wake rhythm: While infants tend to be morning types, adolescents increasingly develop into evening types during puberty. At the age of 17 to 20, a development towards the morning type is observed again, which is considered a marker for the end of adolescence. Women tend to reach the peak of maximum evening preference earlier than men.
Designations
The chronotype is usually determined using validated questionnaires, but can also be determined using an actigraph or by measuring body temperature. The terms morning (“lark”) or evening type (“owl”), or normal type, only describe the temporal position of our inner clock in comparison to all people examined so far.
About 40% of the adult population belongs to one of the two extreme groups (“lark” or “owl”), while 60% are normal types. "Normal type" does not mean "healthy" or "not abnormal", but represents the largest group of all people tested. Determining the chronotype can provide information about health behavior, state of health, personality and mood, e.g. B. when we are most productive, most slack, most irritable and most creative.
Social Jetlag - What does it mean?
The social definition of working hours and leisure activities influences our preferred sleeping habits. For late chronotypes, imposed schedules such as early work or lecture times lead to an increasing sleep deficit during the week, which is compensated for at the weekend.The fact that many people in our society shift their sleep and activity times by several hours between the work week and weekends (or other days off) is comparable to jet lag. Social jetlag describes the difference between external (social) timers and the individual inner clock. To some degree, morning types also experience social jet lag on days off, when they stay up late without the opportunity to sleep in longer the next morning due to their normal circadian wake-up time. In general, social jetlag and the associated lack of sleep can have a negative impact on academic performance among students, among other things, and is also causally related to coping strategies such as alcohol consumption and smoking. Social jet lag can be minimized or even eliminated by changes in the way society is organized (e.g. flexible working hours, adjusted school start times).
Our internal clock
Learn in science comic "Our internal clock - How your body knows the time" by the TUM Professorship Chronobiology and Health (Prof. Spitschan) at the Faculty of Sports and Health Sciences (Weinzaepflen, C. & Spitschan, M. (Ed.) (2021). Enlighten your clock: How your body tells time. (C. Weinzaepflen, Illus.)) more about how light affects our circadian rhythm and how environmental influences affect our body clock.
The science comic is free to download and available in multiple languages!