Rather in the country with the chickens
Is the world still okay at six in the morning? Many people consider this to be a rumor, who then have to be awake and approachable. Depending on the inner clock setting, six is even felt to be five for some - only the inexorable clock doesn't believe them. Time researchers consider this an underestimated problem and are now underpinning the fear with data from all corners of Germany.
What's missing in winter - by the way, we're having one right now - apart from snow and cold, is daylight. And so it is quite possible for the modern open-plan office nomad between Munich and Duisburg not to see the sun for days on end: In the morning before sunrise for the bus, in the evening fumbling for the front door key in the dark. However, there is a small difference between Munich and Duisburg: If the Bavarian is standing at the bus stop at eight o'clock in the morning, his colleague in the Ruhr area has to wait around half an hour for the sun to finally come up torments the horizon. Even if eight in the morning is eight in the morning: Munich is not Duisburg. Geologists explain this with the longitude and the tilt of the Earth's axis.
You could actually say that Munich in winter is more like, say, Görlitz. Because purely in terms of dawn, the self-proclaimed northernmost city in Italy and the actually easternmost place in Germany in Saxony are quite close: sunrise on January 23 was almost ten to eight in both places. Till Roenneberg and his research colleagues are now proving, among other things, why in some respects Munich feels more like Duisburg than Görlitz in the morning for its residents.
Roenneberg, himself at the Ludwig Maximilians University in Munich, is a chronobiologist and, together with European colleagues, is researching the harmful consequences that can have if the time of day, working hours and internal clocks are not synchronized. To do this, the scientists evaluated data material that 21,000 volunteers had provided them with while filling out an extensive questionnaire, in which they provided details about their sleeping and waking habits and the personal daily form curve that is dependent on this. The participants from all regions of Germany learned from the evaluation to which "chronotype" they personally belong - i.e. how their personal inner clock is set and stamps them as the preferred early riser or late bedtime person. Roenneberg and Co, the data set can provide a few more answers.
The researchers were particularly curious about the differences that were noticeable between Munich, Görlitz, Duisburg and all the other large and small places of residence of those who completed the questionnaire. Among other things, they had to show whether the half hour that can lie between sunrise in Saxony and Westphalia is reflected in the chronotypes of the people living there.
Do you generally prefer to get up a little earlier in Regensburg than in Recklinghausen? This actually has to be the case, because the role played by the sun as the light-giving "timer" of the internal clock has long been clarified: Light in the morning confirms the beginning of the day for the body, to which day-active beings ideally base their circadian 24-hour rhythm should. Light that suddenly seems dazzling on what feels like an evening after a flight to Chicago, for example, gradually causes the body awareness and circadian daily rhythm to adjust to the changed conditions. Even in this extreme situation, which evolution has hardly considered, this readjustment of the internal clock usually works quite well - after a transitional period that feels like jet lag.
However, the modern world of work requires many to ignore the natural time marker of sunlight – the early shift starts at five in Duisburg and Görlitz, and night shifts in the hospital are supposed to turn the bright morning into evening. As chronobiologists have been complaining for a long time without consequences, this often takes a toll on the soul and body – but surprisingly often the adaptable body even succeeds. There must therefore also be "social" timers that can outperform the natural timer light in an emergency. Perhaps, Roenneberg's team asked themselves before evaluating the questionnaire, such man-made social adjustment screws override the internal clock across Germany even over the effect that the early and late sunrises from east to west have on the Germans?
The researchers are now presenting two answers: yes and no. On the one hand, the expected influence of the different beginnings of the day can be clearly identified: In the east, from Rügen to Reit im Winkel, the average of all chronotypes is a little earlier than in western Germany. So the internal time of humans is really adjusted to the local time given by the sun. But this, the second part of the finding, only applies to small town dwellers, i.e. when comparing the approximately 60,000 people from Görlitz with the around 270 people from Isenbruch who live in the westernmost village in Germany on the Belgian border. In the 20 cities with more than 300,000 inhabitants, on the other hand, an increasingly dwindling influence of geographic location on the daily rhythm can be demonstrated. If you live in densely populated Munich or the Ruhr area, then social zeitgebers obviously override the natural stimuli provided by the course of the sun, conclude Roenneberg and his colleagues.
The fact that this happens in big cities is probably mainly due to the fact that the sun is becoming less important behind artificial light in offices and shopping malls, which means that the time indicator light makes increasingly vague statements about the beginning of the day. Studies had previously been able to show that if there is a lack of readjustment stimuli, the circadian rhythm gradually shifts towards the evening - which could actually be read from the data from the urban centers.
Overall, more consideration should be given to people's individual chronotypes in schools and companies, believe Roenneberg and colleagues. Of course, this is important in metropolitan areas – but especially outside of the twenty largest cities in the sparsely populated regions, where more than 80 percent of all Germans live. The less the local solar time, which determines circadian rhythms here, with the artificial local time determined by the time zone, the less the society's claim to standard time and one's own bodily feeling should correspond.
Görlitz got it pretty good, by the way: the reference point for the artificial "Central European Time" is the 15th of December.east longitude, and it is here, before the atomic clock came into fashion, that the zone's definitive "local mean time" was set. In Germany, this actually happened regularly in Görlitz, which lies exactly on the meridian in question - and therefore the local solar time and Central Europe's mean art time are also identical here. Isenbruch and its surroundings are 36 minutes behind.
