April instead of March Is the time change now getting a time change?

The six-monthly time change has been the subject of intense debate for years. Now there's a new idea: postponing the time change itself.

Keystone-SDA

29.03.2025, 16:15

SDA

The first weekend in April is better suited to the time change in spring than the last Sunday in March, say two Spanish researchers. This would provide more favorable morning light conditions for a good start to the day.

From a physiological point of view, it would also make sense to end summer time in the EU at the beginning rather than the end of October. The researchers argue that if summer time starts too early, a greater proportion of human activity will be shifted to the dark hours of the morning.

The return to winter time should therefore take place before the main start of activity before sunrise. This year, the clocks will be set forward by one hour on March 30 and back again on October 26.

Discussion misses the biological point

Jorge Mira from the University of Santiago de Compostela and José María Martín-Olalla from the University of Seville are convinced that the time changeover is currently being discussed incorrectly: it does not shift the rhythm of people's lives in relation to the sun at all, but on the contrary, the changeover brings the morning start of all activities back into line with sunrise.

The Spanish National Assembly had already made this kind of seasonal adjustment in 1810. "Social life is simply reorganized because the length of the day in summer makes it possible to do things earlier in the morning than in winter," explained Martín-Olalla.

"The problem is that in recent years [the time change] has only been associated with saving energy, when in reality it is a natural adaptation mechanism."

Daily rhythm is based on sunrise

This is demonstrated by current and historical examples of societies with later activity in winter and earlier activity in summer, corresponding to the synchronizing role of morning light for our bodies.

An analysis of Swedish data from 1746, for example, showed that people got up three and a half hours earlier in summer than in winter.

Even in tropical societies without access to artificial light, people generally get up at dawn and go to bed around three hours after sunset, explain Mira and Martín-Olalla. The human physiological daily cycle is always based on sunrise.

Tip: change the alarm clock gradually

The Spanish research duo have a piece of advice for people who suffer a lot from the time change every six months: adjust in advance. The alarm clock can be adjusted by a quarter of an hour towards the "new" time every week, starting three weeks before the date.

In 1980, daylight saving time was introduced in the Federal Republic of Germany and the GDR, which is still in force every six months. It has been in force throughout the EU since 1996 and begins on the last Sunday in March.

The clocks are set back again on the last Sunday in October. Mira and Martín-Olalla now discuss the physiological and social basis and effects on health in the British Royal Society's journal "Open Science".

Researchers: risk-benefit balance distorted

In recent years, there have been a number of studies on the consequences of the six-monthly time change, such as more traffic accidents in the days following the change and health problems such as temporary sleep disturbances and briefly increased heart attack rates.

The Spanish researchers also say that the biggest disadvantage of the time change is the problems associated with the transition times. However, no really relevant danger can be identified. The short-term slight increase in the risk of accidents or heart attacks, for example, is small compared to the influence of numerous other factors.

In addition, the methodology of such studies is often questionable, writes the research duo. Opinions and analyses by chronobiologists or sleep physicians, for example, often focus exclusively on the disadvantages and ignore the positive aspects of starting work closer to sunrise, which are often forgotten today. The risk-benefit balance is presented in a distorted way.

What would be the consequences of abandoning the time change?

When calling for an end to the time changeover, it should also be borne in mind that its abolition could have far worse consequences than the changeover itself: By switching to summer time, people gain hours of daylight for leisure activities, for walks, outdoor sports or a few hours at the beach.

This promotes well-being and health: "If the day is divided evenly between sleep, work and leisure, one hour accounts for 12.5 percent of available free time."

According to the study, earlier medical opinions on seasonal summertime emphasized people's urgent need for more light, air and sunshine. In many cases, the focus was on improving living conditions - and not on economic issues. Summer time in Italy, for example, was introduced in 1964 accompanied by comments about psychological improvements.

People love long summer evenings

Another aspect: sleep physicians argued for the abolition of daylight saving time, as the researchers explain. However, the general preference among the population is different: Many people love the current situation in summer and enjoy their longer leisure time in daylight. When asked in surveys to choose between permanent summer or winter time, they overwhelmingly opt for the former.

However, Mira explained that permanent summer time also contradicts human physiology. Medical experts point out that people need the blue light of sunlight to wake up. Teachers' associations criticize the fact that pupils would have to walk to school in the dark on many more days without the switch to winter time.

Ultimately, a decision between perpetual summer or perpetual winter time is like choosing to wear sandals in winter or boots even in summer, according to the researchers.