Abolish summer time? Here's what science says

Figure 1: The abolition of daylight saving time in Germany and Europe is repeatedly discussed. As studies show, the clock change does affect health and wellbeing.

Every year, on the last Sunday in March in Germany, the clocks are moved forward by one hour. We “lose” an hour of sleep but can enjoy longer, brighter summer evenings. However, many experts now argue in favour of abolishing daylight saving time entirely. In this blog post we explain the arguments against the clock change. We also discuss the physical effects the switch to daylight saving time can have and present seven tips to help your body adapt more quickly to the new clock time.

Figure 2: Our internal clock cannot simply be reset from one day to the next. Many people need several days or even weeks before their body is fully accustomed to daylight saving time.

Many people consider the ongoing debate about abolishing the clock change exaggerated. Getting up an hour earlier or later — can that really make such a big difference? In fact, our internal clock is much more sensitive than is often assumed. The human sleep–wake rhythm is largely governed by the circadian rhythm. This biological cycle lasts roughly 24 hours and is mainly synchronised by daylight. When the clock is suddenly moved forward by one hour in spring, this rhythm falls out of sync: social time (for example work or school schedules) no longer matches the body’s biological time — and that can have noticeable physical consequences.

A common effect of the clock change is the so-called “social jetlag”. The body is still on the old rhythm while everyday life already follows the new clock time. This creates a state on a physical level similar to flying across several time zones. Typical symptoms such as tiredness, concentration problems, poorer sleep quality, reduced performance and irritability often occur after a clock change. Many people need several days and sometimes even weeks to fully adapt to the new rhythm. The spring clock change is often experienced as particularly stressful because it shortens sleep time.

Another important factor is the chronotype — the individual biological tendency for when people prefer to sleep and be awake. People with the evening chronotype (“owls”) in particular often find it difficult to get used to daylight saving time because their natural sleep–wake rhythm is much later than the societal average. The same applies to teenagers, who are often more active in the evenings and wake later in the mornings. At the same time, an early school start usually requires getting up early. If people continually live against their internal clock, this can have long-term health consequences, including chronic sleep deprivation, persistent tiredness and an increased risk of obesity. The clock change further exacerbates this existing discrepancy between biological rhythm and societal demands.

What does the science say about abolishing daylight saving time?

Figure 3: An important argument for permanent standard time is that it corresponds most closely to the circadian rhythm of most people.

There are still only a few scientific studies on whether daylight saving time should be abolished. There is, however, broad consensus that permanent daylight saving time would not be sensible. Although long, bright evenings sound positive at first, longer daylight in the evening would likely lead to even later bedtimes — and most people already have a sleep deficit. The majority of experts and chronobiologists therefore advocate abolishing the clock change and returning to standard time (winter time). The main arguments for this step are presented below.

1. Circadian rhythm

Because daylight saving time aligns less well with human circadian biology, the American Academy of Sleep Medicine (AASM) calls for the introduction of permanent standard time. Without abolishing the clock change, increased morning darkness and longer evening light in summer would artificially shift the circadian rhythm later. A recent US study compared three scenarios: permanent standard time, permanent daylight saving time and the current biannual clock change. The researchers concluded that permanent standard time imposes the least burden on the human internal clock, as it provides daylight that synchronises better with the circadian rhythm than the other two options.

2. Position of the sun

Another frequently cited argument in favour of permanent standard time relates to the sun’s course. Winter time is the time rule under which sun position and biological clock are best synchronised. By not forcing people to live long-term against their circadian rhythm through the clock change, overall public health could, according to many experts, be significantly improved.

3. Reduction of cardiovascular disease, migraine and obesity

More and more scientific studies are also examining the possible negative effects of daylight saving time on health. For healthy people without pre-existing conditions, the clock change is usually not a major problem. However, those who already have chronic illnesses or belong to risk groups are more likely to experience health deterioration.

A review of cardiovascular risks showed that the number of heart attacks — especially in the first week after the spring switch to daylight saving time — increases moderately. The researchers cite sleep loss caused by the clock change and circadian desynchronisation — a disturbance of the natural biological rhythm — as possible causes. A US county-level modelling study also indicates that permanent standard time, compared with the current switching policy, would reduce new strokes by about 0.09 per cent and the obesity rate by about 0.78 per cent.

In addition, a survey at the Pain Clinic Kiel showed that the frequency of migraine attacks increases by 6.4 per cent in the week after the spring clock change. A notable rise in migraine cases was observed particularly on the Mondays immediately following the switch.

4. Less daytime sleepiness

Abolishing daylight saving time could also reduce the daytime sleepiness typical after the clock change. A systematic review investigating sleep and sleepiness in relation to the clock change supports this assumption. The analysis of a total of 27 studies found that the switch to daylight saving time in spring is often associated with shorter sleep duration and poorer sleep quality. As a result, daytime sleepiness increases, which is especially noticeable for evening chronotypes (“owls”).

5. Fewer traffic accidents

A large US analysis examined 732,835 fatal traffic accidents between 1996 and 2017. It showed that the risk of fatal car accidents rises by about 6 per cent in the week after the switch to daylight saving time. That corresponds to an average of about 28 additional deaths per year in the USA. The researchers attribute this effect to the already mentioned sleep loss and circadian misalignment that can occur after the clock change. Sleep deprivation is known to increase attention errors and reaction times in road traffic, which can lead to more accidents in the short term.

From morning light to reducing caffeine: 7 tips to adapt more quickly to daylight saving time

Figure 4: With a few simple measures you can make the switch to daylight saving time significantly more comfortable and help your body adapt more quickly after the clock change.

It currently seems likely that any abolition of the clock change in Germany and Europe — if it is implemented at all — may still be some time away. Until then, it is important to support the body as best as possible when transitioning to the new time. The following tips and strategies can help make the switch to daylight saving time more comfortable without throwing the natural sleep rhythm too far out of balance.

• Shift your bedtimes forward gradually: Preparation for daylight saving time should not start only on the weekend of the clock change. Ideally, you should move your bedtime forward by 15 to 20 minutes a few days beforehand. The same applies, of course, to wake-up times. This helps your body get used to the new rhythm and avoids a “mini-jetlag” in the days after the clock change.
• Get as much daylight as possible in the morning: Natural light is the most important synchroniser for our circadian rhythm. Exposing yourself to light in the morning after the clock change helps the body recalibrate the internal clock. A short morning walk in the fresh air also gets the circulation going and prevents daytime tiredness.
• Reduce screen time and bright light in the evening: Blue light emitted by many digital devices acts directly on the hormonal sleep system. If you use a smartphone, tablet or TV in the evening, the blue light suppresses the release of the sleep hormone melatonin. As a result, the internal clock shifts later. Many sleep specialists and chronobiologists therefore recommend reducing bright screen light and other artificial light at least two to three hours before bedtime.
• Avoid caffeine from at least midday onward: Consuming coffee and other caffeinated drinks too late in the day can delay sleep onset and make falling asleep more difficult. Avoid coffee, cola or energy drinks in the late afternoon and evening.
• Schedule regular, purposeful exercise: Physical activity also has a major influence on the circadian rhythm. Exercise signals to the body that it is in the active daytime phase. In addition, activity increases sleep pressure, making it easier to unwind in the evening. This applies only if you do not train intensively late in the evening. Moderately intense activities in the morning or early afternoon (e.g. easy jogging, cycling, yoga) are much more suitable.
• Avoid heavy meals in the evening: Eating too late can also stress the body and disturb nocturnal rest. Have your last main meal at least three hours before bedtime; it should ideally be rich in high-quality protein (e.g. fish, lean meat, cottage cheese) and low in fat.
• Be patient and kind to your body: Many people need several days for their body to fully adapt to daylight saving time. If possible, avoid scheduling important appointments immediately on the Monday after the clock change. Instead, be patient with yourself and plan regular breaks to make the transition to daylight saving time easier for your body.

Disclaimer

This article does not replace treatment by a qualified therapist. The basis of this contribution is studies and current literature. It should not be used for self-diagnosis or self-treatment. Discuss any insights from this article with a therapist you trust, if necessary.

Biography

Katharina Korbach regularly writes blog posts about medicinal plants and natural active ingredients for the Narayana Verlag. She developed an interest in language early on and began writing her own literary texts. A serious illness during her A-levels prompted an intensive engagement with health and nutrition topics that continues to this day. After repeated failures of conventional medical treatments, she opted for a more self-empowering, naturopathic therapeutic approach. A plant-based diet was an essential key on her path to recovery.

Katharina studied Cultural Studies (B.A.) and Applied Literary Studies (M.A.). In 2022 she published her debut novel "Sperling" with Berlin Verlag. She currently lives in Berlin as a freelance author, medical editor and lecturer. In her free time she prefers to spend time with friends or at barre training. She also loves to travel and try new vegan recipes.

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Figure 1: Berit Kessler/shutterstock.com ; Figure 2: fizkes/shutterstock.com ; Figure 3: kanyanat wongsa/shutterstock.com ; Figure 4: Me dia/shutterstock.com

26.03.2026