Performance: Why companies should let their employees sleep in

From the Handelsblatt archive: The internal clock has a significant impact on productivity. Nevertheless, many people work against their own rhythm. How can this be prevented?

The biological rhythm: Our internal clock ticks differently depending on genetics, age and light environment. Photo: Getty Images [M]

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.

Owl or lark? The rhythm of the internal clock

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 (awake, productive) and night mode (shutting down, regeneration).

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.

Nocturnal: People who are naturally late risers are considered owls. Photo: Getty Images/500px

“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. So when the body actually wants to sleep, but can't because the person has social obligations.

“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. And not only that - according to Roenneberg, good sleep is also important for productivity and therefore a career factor. Studies also show that those who work with their internal clock are more creative, more charismatic and make better decisions.

The “Early Riser Bias” – and why companies should rethink

Although good sleep has been proven to improve job performance, chronotypes have so far played little role in many companies. Camilla Kring, one of the world's leading experts in chronobiology and author of several books, has observed 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.” One reason: managers themselves are often early adopters. Accordingly, they often expect their team to be visibly present in the morning.

Many employees work against their internal rhythm. “This is particularly fatal in knowledge work,” says Kring. Because these are not mechanical activities, but rather a cognitive performance that depends on concentration, ability to pay attention and memory.

“Some people can handle complex thought processes well in the early morning,” says Kring. “Many others are only able to do this in the afternoon or evening.” 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. Particularly critical: the internal clock also influences the ability to make decisions. According to the expert, lack of sleep and working at an unfavorable biological time lead to people reacting more impulsively and less patiently. 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.

Companies that rely on rigid core working hours, says Kring, lose a massive amount of resources and innovative strength. “Your employees are wasting valuable energy just to compensate for a time structure that is unsuitable for them.”

Organizing working hours according to your internal clock

So what can companies do to provide their employees with better working conditions? Camilla Kring names five measures:

Record chronotypes: Companies should record the chronotypes in their companies. Kring recommends that managers take a test themselves to see which type they correspond to and also motivate their employees to do the same. “On this basis, managers can then discuss with their employees when they can work with the most concentration - and when not.”

Use the time window: If you are at your best in the morning, you should be able to work with concentration in the early hours. Owls, on the other hand, should be able to schedule cognitively demanding tasks in the afternoon or evening.

Protect power hours: Employees should be able to work undisturbed during these time windows. In a company that Kring worked with, she introduced a button that signals when employees are in phases of concentration - and should not be disturbed.

Schedule meetings wisely: Meetings should only take place at times when the natural waking periods of most chronotypes overlap. “The core working hours should be between ten and 3 p.m.,” says Kring. Where shift work is necessary, rosters should also be more closely aligned with chronotypes. In a Norwegian company, for example, meetings were only allowed to start at ten o'clock. According to Kring, satisfaction rose from 48 to 95 percent.

Set communication standards: “If a late-night guy writes an email late in the evening, a lark shouldn’t feel obligated to respond immediately,” says Kring. Conversely, no one who is online at six in the morning should expect that the entire team will start working immediately.

Michael Wieden knows what such measures can look like in practice. He is a consultant and has supported many large projects in chronobiology.

Wieden implemented one of his best-known projects with the Wartenberg Clinic. This is about 50 minutes by car from Munich. Employees there were able to voluntarily have their chronotype determined using a blood test. The clinic then adjusted the working hours and shift times: late risers worked in the afternoon or evening, as far as possible, and early risers worked in the morning.

The result: daytime fatigue fell by 72 percent. “Which in turn led to better concentration and a lower risk of errors,” says Wieden. In addition, the number of employees with more than three days of illness fell by 48 percent. The concept is now firmly anchored.

The “ChronoCity” project was even bigger. From 2012 to 2016, Wieden supported the project as an economic developer. The town of Bad Kissingen in Franconia (around 50,000 inhabitants) was supposed to be the world's first chronobiological town. The aim was to anchor chronobiological principles throughout everyday life: schools should start later and lighting was optimized. Clinics planned to align shift work and even surgical plans with the chronotypes. Companies were also looking into changing their rosters accordingly.

“In the end, the project ended after four and a half years due to political and structural hurdles.” Wieden still draws a lot of positive things from this. “It serves as a model for international initiatives,” he says. He recently reported on Chronocity at a meeting of the “Time Use Initiative” in Barcelona. This is an initiative that works to ensure that time structures in everyday life are better organized.

According to Wieden, for such initiatives to work in the long term, one thing is needed above all: someone who can permanently anchor the measures in an organization. “Many chronobiological pilot projects are successful,” he says. “As soon as the project period is over, they often fizzle out.” Therefore, it must be determined in the study design how the measures will continue after the end of the project. “A breakthrough occurs when the consideration of chronotypes is included in the company agreement,” says Wieden. Just like at the Wartenberg Clinic.