On the night of Saturday March 30 to Sunday March 31, we will go from 2 to 3 a.m. in the blink of an eye. This will be the time to welcome the change to summer time. Is it as harmless as it seems? What are the effects of the time change on our health?
Scientific literature shows that the time change does indeed have physiological and health effects: it impacts our internal biological clock, called the circadian system, and can induce harmful effects on our health (sleep disorders, alertness, accidents). work and the road, depression, myocardial infarction and stroke).
The body’s adaptation to this time difference that we impose on it varies from one individual to another and can last from a few days to several months. In the context of this time change, small children and the elderly are more likely to feel negative effects, but this is also the case for adolescents, night workers, and all those suffering from a sleep disorder, who will have more difficulty adapting to the new schedule.
The transition to summer time more difficult to manage
According to the opinion of specialists, such as the neurobiologist and Inserm researcher Claude Gronfier, president of the French society of chronobiology, the transition to summer time would be more complicated for the body to manage than the transition to daylight saving time. ‘winterwintertaking into account, on the one hand, the loss of an hour of sleep, and on the other, the fact thatbiological clockbiological clock must be brought forward by one hour.
On average, our bodies tend to fall behind by 10 minutes in their 24-hour cycle. With the time change, we would ask them to advance their pace by an hour, which would increase the efforts made by our body to try to catch up. This change would be particularly badly experienced by the latest chronotypes, that is to say people who are on average 30 minutes late in their 24-hour cycle. The effects of the transition to summer time on our circadian rhythm would be accentuated by the general lack of sleep among the French population, estimated between 30 and 90 minutes per day according to studies (60 minutes according to barometerbarometer 2022 from the National Institute of Sleep and Vigilance).
What is better to prioritize? Summer time or winter time?
With the abolition of the seasonal time change having been voted on in 2019, EU member states must now choose which definitive time to adopt. The vast majority of the scientific community recommends that the choice be doordoor on maintaining winter time.
If we were to maintain summer time all year round, waking up in winter and going to bed in summer would indeed be more difficult. The shortest day of the year, December 21, sunsun would rise in Paris at 9:41 a.m., instead of 8:41 a.m. standard time (or “winter time”), and a very late sunrise on this seasonseason winter would have a harmful impact on the health of the French, the adjustment of our biological clock is also done through exposure to light. When we wake up, our body needs a large dose of lightlight to start a new day and synchronize the biological clock. It would thus be deprived of this light in winter with a later sunrise.
On the other hand, if winter time were maintained, sunset would take place on average 4 hours later in summer than in winter, instead of 3 hours with the current time change, and would induce a later sunset. early and longer sleep which would be beneficial to our health.
The importance of light
Work on the importance of exposure to light on the circadian cycle is being carried out at the Lyon Neurosciences Research Center. The research team observed in particular that certain exposures to light, at very specific times, have beneficial effects on the physiology of sleep and the body’s non-visual functions such as the secretion of melatonin (hormonehormone controlled by the circadian clock and involved in the regulation of sleep), the pupillary reflex, brain activity, temperature and the cardiovascular system, even at very short exposures and very low levels of light.
Inserm article, published on March 27, 2022
Every year since 1976, the old quarrel between the For and the Against. For or against summer time? Some people see their sleep schedule disrupted while others feel no effect. By disrupting the circadian rhythmcircadian rhythm, what are the effects of this time difference on our body? What does science say about this?
On the night of Sunday March 27, our phones and other connected devices will jump back one hour in time. The time displayed on the screens will automatically change from 2 to 3 a.m. to accompany the transition to summer time. If, for most people, this time change will have little or no visible consequences, several research studies nevertheless underline that it can be associated with effects on our biological clock and with significant consequences on our health.
Scientific literature shows that the time change does indeed have physiological and health effects: it impacts our internal biological clock (called the circadian system) and can induce harmful effects on our health (sleep disorders, alertness, accidents). work and the road, depression, myocardial infarction and stroke).
The body’s adaptation to this time difference 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). In the context of this time change, small children and the elderly are more likely to feel negative effects, but this is also the case for adolescents, night workers, and all those suffering from a sleep disorder and who will have more difficulty adapting to the new schedule.
Disadvantaged night owls
Furthermore, according to the opinion of specialists, such as the neurobiologist and Inserm researcher Claude Gronfier, president of the French Society of Chronobiology, the transition to summer time would be more complicated for the body to manage than the transition to summer time. winter time, taking into account on the one hand the loss of one hour of sleep, and on the other the fact that the biological clock will have to be advanced by one hour.
On average, our bodies tend to fall behind by 10 minutes in their 24-hour cycle. With the time change, we would ask them to advance their pace by an hour, which would increase the efforts made by our body to try to catch up. This change would be particularly badly experienced by the latest chronotypes, those recording an average of 30 minutes late in their 24-hour cycle. The effects of the switch to summer time on our circadian rhythm would be accentuated by the general lack of sleep among the French population, estimated between 30 and 90 minutes per day according to studies (60 minutes according to the Institute’s 2022 barometer National Sleep and Vigilance).
Why maintain summer time and winter time?
The abolition of the seasonal time change having been voted in 2019, the member states of the European Union must now choose which definitive time to adopt. The vast majority of the scientific community recommends that the choice be made to maintain winter time.
If we were to maintain summer time all year round, waking up in winter and going to bed in summer would indeed be more difficult. On the shortest day of the year (December 21), the sun would rise in Paris at 9:41 a.m. (instead of 8:41 a.m. in standard time or “winter time”), and this sunrise Very late sun in this winter season would have a harmful impact on the health of the French, the adjustment of our biological clock is also done through exposure to light.
When we wake up, our body needs a significant dose of light to start a new day and synchronize the biological clock. It would thus be deprived of this light in winter with later sunrise.
On the other hand, if winter time were maintained, sunset would occur on average 4 hours later in summer than in winter, instead of 3 hours with the current time change, and would induce a later sunset. early and longer sleep which would be beneficial to our health.
Work on the importance of exposure to light on the circadian cycle is carried out at the Lyon Neurosciences Research Center. The research team observed in particular that certain exposures to light at very specific times have beneficial effects on the physiology of sleep and the non-visual functions of the body such as the secretion of melatoninmelatonin (hormone controlled by the circadian clock and involved in the regulation of sleep), the pupillary reflex, brain activity, temperature and the cardiovascular system, even at very short exposures and very low levels of light
