Daylight saving time in Europe ends on October 31

**On Sunday, October 31, 2021, the clocks were turned back by 1 hour in most of Europe, when daylight saving time (DST) ends.**

In most European countries, the clock is set back one hour on October 31, 2021, 01:00 UTC. As Europe spans several time zones, the change occurs at different local times. The United States will return to its original position a week after Europe on November 7, 2021.

The summer-winter time system was adopted by European countries in the last century to save the energy, especially during the war or the crises of the oil market in the 1970s.

*This mechanism of changing the time twice a year would have negative effects on our health*, according to new research. Gisela Helfer, senior lecturer in physiology and metabolism at the University of Bradford, England, explains in an [article published in The Conversation](https://theconversation.com/changement-dheure-cinq-conseils-pour-mieux-sy-adapter-170814) on how we can adapt our body.

In the first few days after changing the time, many suffer from various symptoms such as irritability, insomnia, fatigue during the day and reduced immune function. More worrying is what the heart pathways, stroke and more frequent work accidents in the first weeks are after the time change. It was also found that in the week leading up to daylight saving time, there is a 6 percent increase in the number of fatal road accidents.

# How does changing the clock affect us?

The reason why the time change affects us is related to our biological clock. This internal clock controls our basic physiological functions, such as hunger or fatigue. This rhythm is known as circadian rhythm and lasts about 24 hours.

# The role of the internal biological clock

All of these processes are governed by our internal biological clock, many of whose quadrants are controlled by a “master clock” located in a part of the brain called the hypothalamus. While each of our tissues and organs has their own clock (the so-called peripheral clock), the main clock in the brain has the role of synchronizing them all and ensuring that they are all working in harmony at the right time of day.