Summer or winter time? Debate over fixed time in the context of public health

Many of us have been complaining for years about having to change our clocks twice a year. Changing the time can be troublesome, and numerous studies indicate that it may negatively affect well-being, sleep quality and health. In response to these concerns, more regions are considering introducing one, constant time throughout the year. However, the choice between standard time (so-called winter time) and summer time is controversial.

Summer or winter time? A duel of arguments

Supporters of permanent summer time emphasize that longer, bright evenings are conducive to recreation, physical activity, socializing and have a positive impact on the economy by enabling longer shopping or using services. However, experts warn that such a decision has serious health consequences. Moving dawn an hour later means more people, including children and teenagers, will have to get up, travel to school and work in the dark on winter mornings.

In turn, permanent winter time better corresponds to the natural human circadian rhythm. Morning light is crucial for the synchronization of the biological clock, it affects the quality of sleep, mood and general functioning of the body. Evenings will be darker, but mornings will be brighter, which - as scientists emphasize - is better for health. As the authors of the analysis explain, exposure to morning light helps maintain normal circadian rhythm, while evening light may disturb it. Shifting the morning light to later hours, as is the case with permanent summer time, especially in winter, may lead to dysregulation of the biological clock.

Negative effects of permanent daylight saving time

This is especially important in the context of mental health. Studies conducted in Canada have shown that up to 15 percent of the population experience mild symptoms related to lack of light, such as low mood, sleep problems, changes in appetite and loss of energy.

Geographical research shows that people living in the western time zone, where the sun rises later, are more likely to suffer from health problems.

Children and adolescents are particularly vulnerable, as their sleeping hours naturally shift during adolescence and school obligations force them to get up early. Shift workers, people using public transport, pedestrians and cyclists, as well as residents of less lit or poorer neighborhoods may also feel the negative effects of permanent daylight saving time.

Experiments with constant daylight saving time

History shows that experiments with permanent daylight saving time do not necessarily end with success. The United States implemented permanent daylight saving time during the 1974 energy crisis, but reversed the policy within a year amid opposition to dark winter mornings and concerns about children traveling to school before sunrise.

Russia introduced permanent daylight saving time in 2011, but withdrew the decision in 2014 amid public dissatisfaction.

Chile similarly abandoned its nationwide implementation of permanent daylight saving time after an experiment in 2015.

Element of health policy