Berlin. Nine o'clock morning conference, ten o'clock jour fixe, eleven o'clock the first customer appointment: the German working world is not made for late risers. Core working hours are not legally required in Germany, but in many offices people work between nine a.m. and 5 p.m. - and therefore often against their own biological rhythm.
Because everyone has it: the internal clock, which is deeply anchored in the genes. Without them nothing works. It controls the sleep-wake rhythm. Our mood. Our metabolism. Also our performance. And yet it is often simply ignored. From each person. From society. The employer. Science shows that if working hours match the rhythm of the internal clock, everyone wins.
The internal clock is located in the brain, specifically in the hypothalamus, a small but very important region in the diencephalon - close to the point where the optic nerves cross. It works like a daily timer that synchronizes the body to a 24-hour rhythm. And it is based on one thing above all: daylight. Depending on whether it is light or dark, the body switches to day mode and night mode.
And yet, biological clocks do not tick the same way for everyone. There are early risers and late risers, known in science as larks and owls, and many degrees of them. Which type someone is depends on their genetics, age and lighting environment and can be determined using a blood test.
“Most people are somewhere between an owl and a lark,” says Till Roenneberg. He is considered one of the most prominent chronobiologists in Germany. So that they also have a bird name, he called them “doves”.
However, social life in almost all areas is geared towards the early chronotypes, although according to research only around 20 percent of people are larks. This leads to a problem for late risers: social jet lag. The term describes the discrepancy between the biological and social time zones.
“The chronotype is a fixed human characteristic that cannot easily be shifted,” says Roenneberg. “The body doesn’t care when we have meetings or when school starts.”
Anyone who constantly works against their internal clock sleeps worse and thus endangers their health. Studies show that permanent social jet lag promotes obesity and diabetes, cardiovascular diseases or mental problems. Those who work with their internal clock are more creative, more charismatic and make better decisions.
Although good sleep has been proven to improve job performance, chronotypes have so far played little role in many companies. Camilla Kring has been observing for years that late risers in particular are often disadvantaged in everyday work.
“Employees who are in the office early are often viewed as more disciplined, reliable, ambitious and leadership-oriented,” says Kring. “Even if late risers work the same number of hours and produce better results in the evening.”
Many employees work against their internal rhythm. “This is particularly fatal in knowledge work,” says Kring. Forcing employees to work while still in their biological night mode has a significant impact on performance.
“Creativity suffers and the susceptibility to errors increases,” says Kring. For example, researchers from the USA were able to prove in 2021 that investment bankers who are early types also made better decisions in the morning, while late types performed better in the evening.
According to Kring, companies that rely on rigid core working hours lose massive amounts of resources and innovative strength.
So what can companies do? Camilla Kring names five measures: record chronotypes, use time windows, protect power hours, schedule meetings wisely and set communication standards.
Michael Wieden knows what such measures can look like in practice. Wieden implemented one of his best-known projects with the Wartenberg Clinic. Employees there were able to voluntarily have their chronotype determined using a blood test. The clinic adjusted the working hours and shift times accordingly.
The result: daytime fatigue fell by 72 percent, which led to better concentration and a lower risk of errors. In addition, the number of employees with more than three days of illness fell by 48 percent.
The “ChronoCity” project was even bigger. From 2012 to 2016, Wieden supported the project in Bad Kissingen as an economic developer. The aim was to anchor chronobiological principles throughout everyday life.
“In the end, the project ended after four and a half years due to political and structural hurdles,” says Wieden. Nevertheless, it serves as a model for international initiatives such as the “Time Use Initiative” in Barcelona.
According to Wieden, for such initiatives to work in the long term, they need someone to permanently anchor the measures in an organization. A breakthrough can be achieved if the consideration of chronotypes is included in the company agreement.
