Every Time change, we are a little lost: should we put the clocks forward or back? We are not the only ones confused by this measure, taken in 1976 to reduce the country’s energy expenditure. OUR body also finds it difficult to adapt.
Our organization follows a 24 hour cycle, also called circadian rhythm. Our sleep/wake system, our cognitive functioning, our body temperature, hormone production, appetite… regulates most of our biological functions.
In humans, this internal clock is located in thehypothalamus. INSERM, which has studied its operation, explains “It is made up of two suprachiasmatic nuclei each containing regarding 10,000 neurons that exhibit oscillating electrical activity over regarding 24 hours. This electrical activity is controlled by the cyclic expression of a fortnight gene clock“.
Work has revealed that the circadian rhythm does not operate in a closed circuit. It relies on daylight, among other things, to continuously sync. THE time changes – whether summer/winter or the result of a time zone change – disturb our internal clockand by domino effect our biological functions.
Jian-Sheng Lin and Claude Gronfier, Inserm researchers from the “Waking” team at the Lyon Neuroscience Research Center, explained in an article from the center that “in general the switching to winter time is less complicated that the change to summer time where you “lose” an hour of sleep. It should also be noted that the effects of the transition to summer time would be accentuated by the general lack of sleep of the French population, estimated between 30 and 90 minutes per day according to studies.
The disorders as well as the rehabilitation time vary however from one individual to another. Generally, fragile people are the most affected. Several health concerns can appear following a change of hours.
Changing the time: sleep, metabolic, cardiac disorders…
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Losing or gaining an hour has little visible consequence for most of us. However, experts agree, those 60 minutes may be enough to disrupt the circadian rhythm in the most sensitive. The metabolism, the functioning of the cardiovascular system, the appetite or even the immune system can be affected.
Scientific literature shows that the time change can induce sleep disorders, alertness, road accidents, depression, suicides, and myocardial infarction, explains INSERM.
“The switch to winter time is reputed to be accompanied by a gain in sleep of one hour, but in the end there is only little evidence for increased sleep duration that night“, confides to Medisite Dr. Sophie Dechaumont Palacin, neurologist and sleep specialist practicing at the Clinique des Cèdres in Toulouse. According to the specialist, “the switching to winter time tends to promote early awakening an hour for the following days, also resulting in the accumulation of a sleep debt throughout the following week.
However, “this sleep debt can induce excessive daytime sleepiness, fatigue and an increased risk of road accidentsperfectly demonstrated following the transition to summer time.”
Regarding summer time, “it is well established that the transition to summer time in the spring leads to an increase in sleep latency and sleep fragmentationresulting in an accumulation of sleep deprivation, at least for the next week, maybe longer.”
Daylight Saving Time: Beware of Heart Attacks
Furthermore, the change to summer time (in March) would be particularly delicate for health. Researchers from the University of Colorado at Denver showed in a study published in 2014 that the loss of one hour of sleep on Sunday caused by this change increased the risk of having a heart attack by 25% on Monday. The following days, it decreases once more. On the other hand, upon arrival of thewinter hourthe scientific team observed a 21% decrease risk of heart attack when you sleep an hour longer.
If the time change can cause trouble, A few days are usually enough to synchronize to the new rhythm.
Switching between summer and winter time: how to prepare for it?
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Several tricks make it possible to limit the effects of the change of time whether it is summer or winter:
- Start gradually shifting your wake-up time by 15 to 30 minutes a few days before.
- Prioritize activities in daylight to help the body resynchronize.
- Go to bed and get up at regular hours.
- Also eat at fixed times whether hunger is present or not.
- Choose healthy foodsrich in vitamins and avoid foods that are too fatty or too sweet to aid digestion.
- Limit the consumption of alcohol and stimulants.
- Avoid screens (TV, smartphones, computer) before going to bed.
- Play sports.
If fatigue is felt, it is possible to take a nap in the early followingnoon. Nevertheless, to avoid delaying bedtime a little more, it is advisable not to not sleep more than 30 minutes.
