Science
Early bird or night owl

When do you do your best work?

Early bird or night owl

Most people perform better later in the day than in the morning. It would therefore be much more efficient to make our working hours more flexible, says retired professor of chronobiology Domien Beersma. But should we abandon the nine-to-five rhythm that is such a hallmark of our society?

By Leonie Sinnema / Video by Robbert Andringa / Animation by René Lapoutre / Translation by Sarah van Steenderen

Early birds and night owls really do exist.

What type of person you are depends on the rhythm of the cells in the suprachiasmatic nucleus: your biological clock.

How your biological clock ticks depends on two factors: heredity and light exposure.

Exposure to artificial light at night has caused more people to be night owls rather than early birds.

For a night owl, having to go to work early can lead to health problems.

Domien Beersma, retired professor of chronobiology, therefore argues that our working days should be more flexible.

However, many people seem to want to stick with the old routine, especially because of the separation between work and private life.

Reading time: 6 minutes (1,317 words)

A full classroom, 9 a.m. While the instructor cheerfully starts the two-hour lecture, sleepy-faced students with bed head continue to trickle into the room. They look around apologetically, or find an empty seat as quickly and quietly as possible. Are they hungover? Perhaps. But do not judge these lazybones or notorious latecomers too harshly. A ticking clump of cells in their brains might just be the cause of their lateness.

Ticking clock hands in your brain

Your chronotype determines the time of day during which you prefer to be most active. This is caused by a clump of rhythmic cells in the suprachiasmatic nucleus, better known as your biological clock. The biological clock is located on the crossroads of your eyes’ nerve bundle and consists of cells that each have their own rhythm. ‘Even if we isolate those cells and keep them alive in a separate box, they maintain that 24-hour rhythm’, explains Domien Beersma.

Together, the cells in your biological clock generate a rhythm of being asleep and being awake, also known as circadian rhythm. For most people, that rhythm is a little longer than 24 hours, but people with a late chronotype (night owls) often have a slower ticking internal clock. Rhythms consisting of 25 hours are no exception in night owls. How slow or fast your internal clock ticks is largely hereditary. The amount of light you are exposed to also plays a role. ‘Even if the clock’s rhythm deviates, daylight will keep that in check’, says Beersma. Together, the two forces determine what time of day you are at your best.

How many people are early birds or night owls is difficult to determine. ‘It’s a matter of definition’, says Beersma. If you ask everyone what time they would prefer to wake up, the answers are more or less distributed normally, with a few extreme outliers in the morning or evening category. ‘But there are relatively few morning people and many more night owls. It never used to be like that.’

Our own doing

Researchers sent two groups of test subjects on a camping trip. One group consisted of people with a late chronotype, the other of early birds. Without the influence of artificial light, the entire group, including the night owls, performed better in the morning.
‘Because of our increasing exposure to artificial light, our biological clock shifts’, Beersma explains. The main culprit is evening light. ‘The evenings are especially long in winter. Evolutionarily speaking, we don’t expect much light after sundown. But that has changed with the invention of artificial light. The cells of our biological clock interpret that light as a setting sun. And when that sun sets late, our biological clock moves with it and we get tired earlier.’

If you are not predisposed to it, it will not happen, but it is a fact that our biological clock functions very differently than it did in the past. ‘It is our own doing as a society. So why not take it a step further and make it easier on everyone? The chance that people will return to the pattern our ancestors had is quite small’, Beersma says.

Not well-rested

The nine-to-five rhythm can have serious consequences for night owls’ health, chronic sleep deprivation being the prime example. ‘Chronic sleep deprivation leads to people functioning poorly. Sluggishness, a higher risk of accidents: these are all connected to sleep deprivation’, says Beersma.

Students suffer from this problem as well, recent research from the Nederlandse Vereniging voor Slaap- en Waak Onderzoek (Dutch Association for Sleep and Wakefulness Research, NSWO) from the University of Leiden and the Brain Foundation has shown. A quarter of the 1,378 students interviewed say that they regularly do not want to study because they are so sleepy. Two-thirds of the students would like to sleep longer. Moreover, sleep deprivation can lead to significantly lower grades.

According to Beersma, the solution is simple. ‘You should have people work at the times they function best. So someone making a work schedule could tell employees that they have a morning or evening shift every once in a while. But they could also decide to have the early bird work the morning shifts and the night owls the late shifts. There will always be a time at night when no one wants to work, but people can probably make it work. You could get so much more done by working like that. We’re so used to a tight schedule that it’s hard to break loose from it. But I think interests on both sides are quite sizeable, including the interests of the individuals. I think that we don’t take those different people into account enough.’

Separating work and private life

But is that something people actually want? The way we view work has changed a lot, says senior lecturer of sociology Rudi Wielers. ‘In the nineties, a nine-to-five job was considered boring and not something people aspired to.’

Yet research shows that the majority of the Dutch professional population prefers to work according to that nine-to-five pattern. ‘That has to do with the fact that many people enjoy the separation between their work and their private lives. Women especially set great store by the rhythm because they coordinate it with their private responsibilities, such as picking up the kids. Slightly older men would be happier with a more flexible arrangement of working hours’, Wielers says.

A preference for a stable rhythm is closely tied to family responsibilities. ‘But I wouldn’t be at all surprised if young people saw it differently’, says Wielers. Should working and studying at the university be made more flexible? ‘Changes in the biological rhythm have drastic consequences for everyone. Besides, we are judged by our productivity. Nobody checks whether or not I’m at my desk at 9 a.m. sharp. For students who often have varying contact hours, a slightly more compulsory rhythm might actually do them good’, he says, laughing.

What do RUG students and staff themselves think of more flexible working hours? The UK took to the streets to find out.

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