“It’s About Time” – Chronobiologists Call for the Abolition of Daylight Saving Time

Following last weekend’s transition from daylight saving time to standard time, several researchers from the BioClock Consortium appeared in the media. In interviews, news articles, and radio and television programs, they provided scientific background to the debate on changing the clocks.

According to the researchers, the discussion is not simply about gaining an extra hour of sleep or enjoying longer summer evenings. It is primarily about health. Their message is clear: both daylight saving time and the practice of changing the clocks twice a year are harmful to our biological rhythms.

With Laura Kervezee

With Roelof Hut

With Maaike van der Rhee

With Joke Meijer

With Roelof Hut

With Laura Kervezee

Morning light

In the media, the chronobiologists emphasize that morning light plays an important role in properly synchronizing our natural sleep-wake cycle. “Humans are diurnal animals,” Maaike van der Rhee told NU.nl. “Light is very important for maintaining a healthy day-night rhythm.” During daylight saving time, the sun rises later, meaning that many people receive less natural morning light at the time when their bodies need it most.

This is especially problematic in autumn, when the sun already rises later. It can lead to a disruption of the sleep-wake cycle. Dr. Laura Kervezee warned in NRC that persistent disruption of the biological clock is associated with sleep problems, fatigue, and, in the long term, an increased risk of conditions such as obesity, type 2 diabetes, and cardiovascular disease.

Permanent daylight saving time?

A permanent daylight saving time would make this problem even worse. In the Netherlands, the sun would not rise until around 9:45 a.m. in the middle of winter. This means that schoolchildren, teenagers, and people who start work early would spend much of their morning in darkness. According to Prof. Joke Meijer, speaking to RTL Nieuws, this is unfavourable for the biological clock and may also have consequences for issues such as road safety.

If it were up to chronobiologists within and beyond the BioClock Consortium, the choice would be straightforward: keep standard time (winter time). Or, as Prof. Roelof Hut explained on Hart van Nederland, even move one hour further west to a time zone that aligns more closely with our biological clock and is therefore the healthiest option.

Want to learn more about the science behind BioClock’s position? Read our position statement here!