“At three o’clock, it will be two o’clock.” Every year, it’s the same refrain: on this last Sunday of October, we switch to winter time. The bonus is that we’ll get an extra hour of sleep. However, now it will be dark an hour earlier.
A change that raises certain questions: How long does the body take to get used to this jet lag? Physiologically, how does the body adapt to the change to winter time? Can we be jetlagged by the time change? Is it possible to feel it passing smoothly?
Jet lag and disturbed sleep
With a time change that will allow us this Sunday to sleep an extra hour, “the transition to winter time is much less difficult for the body than the transition to summer time: we have a longer day and a longer night’s sleep as well,” explains Dr. Sylvie Royant-Parola, psychiatrist specializing in sleep disorders. Thus, night owls are those who will best appreciate this change to winter time. “It’s much better experienced by people who are in the evening, who sleep a little later and who will for a few days have the impression of being able to sleep an hour more,” she notes.
Still, we are not all equal on this ground. “Thirty years ago, it was thought that the time change did not have many effects on the body, but many studies have since shown that there is an impact on more sensitive populations. than others to this event, observes the sleep specialist. This is particularly the case for the elderly and people in a phase of depression or with sleep disorders, for whom it will be more difficult to metabolize this time change. This is also the case for young children from one to six years old, who have very fixed time rhythms and who can be affected by this jet lag. They will not sleep an extra hour in the morning and will get up at the same time: for example, by waking up at 7 a.m., i.e. 6 a.m. in the old summer time, they will be more tired, while having more difficulty falling asleep at night.
“The impression of being less on your plate” for some
If the time change is painless for the majority, for the most vulnerable people, “it may be more difficult to adjust to the new time, they will be in a mini-time difference, like when traveling to another time zone. , illustrated by Dr. Royant-Parola. For them, the adjustment can take four to eight days”. The cause: “the change of time chronobiologically induces a shift in the circadian rhythm, our internal clock set to a twenty-four hour day. And this partial desynchronization can cause a feeling of fatigue, with the impression of being less on your plate and more stressed, ”explains the specialist. “Fatigue, drowsiness, headaches, nausea, digestive disorders and loss of appetite, but also mood disorders and reduced cognitive performance” are all problems that some may experience, complete National Institute of Sleep and Vigilance (INSV).
Fortunately, for children, the calendar does things rather well: “They are among the most sensitive, but the fact that the transition to winter time occurs during school holidays means that they do not have to suffer too much from the effects deleterious to their rhythm and their sleep,” notes Dr. Royant-Parola.
Immediately reset your rhythm
However, for people sensitive to the time change or prone to sleep disorders, a few simple measures can help you get through it smoothly. “You have to reset your pace right away,” she recommends. The most effective is to take advantage of natural light as much as possible, rather at noon, since at this time the light is weaker at the beginning and end of the day, for example when going for a walk after lunch to expose yourself to the light “.
Another measure that works: “do a little more sustained physical activity the week of the time change, to train the body to adjust more quickly to the new time, this increases the amplitude of the circadian rhythm” , continues the specialist. And this is valid for young children, “we must take advantage of these vacation days to make them do more outdoor activities”.
Finally, in order not to disturb his sleep further, promoting a serene bedtime is recommended. “Moderate the consumption of stimulants (coffee, coke, energy drinks) and do not absorb any more after 2 p.m.”, prescribes the INSV. He also advises setting up “a bedroom conducive to sleep”, immersed in “darkness, silence, and at a temperature between 18 and 20°C”, and disconnecting from screens “one to two hours before go to bed “. An interval during which we can get closer to the arms of Morpheus by favoring “a calm activity”, such as “soft music, reading or even relaxation”.