THE ESSENTIAL
- During the night from 29 to 30 October 2022, the winter schedule will be changed: at 3 in the morning it will be 2 in the morning.
- Time changes are more difficult for young children, adolescents, the elderly, night workers, and people with sleep disorders to manage.
- Summer or winter time? Most chronobiologists (specialists in the biological rhythm of the organism) tend towards winter because it would allow the organism to have the necessary dose of light upon awakening, and this, all year round. .
It is a consolidated habit more than 40 years ago, in 1976: in spring we switch to summer time and we have to increase the clock by an hour more, in autumn it is the opposite, we switch to winter time and move the hour back one hour. The origin of this idea? An urgent need to save energy by synchronizing the duration of the sun with daily activities. If even today “Pro” and “Cons” discuss the usefulness of such a system, the scientific literature shows that the change of weather really has significant consequences on our health. .
Chronobiology: Changing the time affects our circadian rhythm
The circadian rhythm, or “biological clock”, is the body’s internal clock. Like a conductor, he regulates certain physiological processes, such as sleep and food, in a 24-hour cycle. Its synchronization occurs mainly through light and disturbances of this rhythm are associated with many diseases.
The time changeit affects our internal biological clock and can induce harmful effects on our health (sleep disturbances, disturbances in alertness, accidents at work and traffic, depression, myocardial infarction and cerebrovascular accidents)“, details Insert in an article.
“The body’s adaptation to this jet lag that we impose on it will vary from one individual to another and can last from a few days for morning chronotypes (people who tend to be more efficient in the morning), to several months for late chronotypes ( people who tend to be more efficient in the evening). ” Young children and the elderly are most at risk of experiencing these negative effects. “But this also applies to teenagers, night workers and all those with sleep disorders who will have a harder time adjusting to the new hours.“
The transition to summer time is more difficult for the organization to manage
According to several chronobiologists, including neurobiologist and Inserm researcher Claude Gronfier, president of the French Society of Chronobiology, the transition to summer time would be more difficult for the body to manage due to the loss of an hour of sleep and the fact that the biological clock must also be advanced by one hour.
In 2019 in France, during an online consultation, the abolition of the seasonal change of time was voted. I also vote in favor of the European Parliament and the end of the time change was scheduled for 2021, but member countries are struggling to tune in.
Winter would be healthier
For their part, most French prefer to keep daylight saving time. However, the scientific community recommends opting for the winter time. In fact, with daylight saving time, waking up in winter and falling asleep in summer would be physiologically more difficult.
On the shortest day of the year, December 21, the sun rises in Paris at 9:41 am (instead of 8:41 am for winter time). Coming out of sleep in the morning, the body would therefore not have its dose of light to synchronize its biological clock. However, the scientific team of the Lyon Neuroscience Research Center noted that “certain exposures to light at very precise times have beneficial effects on the physiology of sleep and on the non-visual functions of the body such as the secretion of melatonin (a hormone controlled by the circadian clock and involved in the regulation of sleep), pupillary reflex, brain activity, temperature and cardiovascular system“, And this, “even with very short exposures and very low light levels“.
