We always forget in which direction the hands will turn. At two o’clock in the morning on the night of Saturday March 25 to Sunday, it will actually be three o’clock. Bad news for heavy sleepers who will lose an hour of sleep. How can we try to cushion the shock? We dissect received ideas.
- It is said that the time change can cause sleep disturbances: is it true?
To sleep well, it is important to have a very regular rhythm. That is to say getting up and sleeping at a fixed time. Even an hour can impact our sleep and change our rhythms. “You have to know that we have a clock in our brain which influences the rhythms. We have time windows where it is easier to fall asleep than others”, explains to L’Express Armelle Rancillac, researcher in neurosciences at Inserm (National Institute of Health and Medical Research), sleep specialist. This was also confirmed in L’Express by Sylvie Royant-Parola, president of the Morpheus network, end of 2022: “There is a kind of reset of the internal clock. Having a good training of our clocks will regulate the organization of sleep, but also the rhythms of hormone secretion, the evolution of body temperature, etc.” Thus the time change can upset our sleep routine.
- It is said that you have to change your life-sleep rhythm when the clocks change: is this true?
“During the summer time change, you have to try to eat earlier in the case that interests us. It is important to take these meals at a fixed time”, underlines Armelle Rancillac. It is therefore advisable to adapt. If we get up earlier and don’t go to bed earlier, we will create a “sleep debt”. The solution is therefore to try to go to bed earlier, that is to say, to redo a “twilight” at home. With this in mind, it is recommended to set up a “digital curfew” or at least turn down the volume. From a week before the time change, it may be advisable to wake up gradually a little earlier to gently accustom the body.
“The external temperature is also important, it is recommended to turn off the heating before sleeping so that our body can cool down”, explains the specialist. Another tip: exercise six or seven hours before going to bed. This allows the body temperature to rise, which leads to greater cooling. Rather than getting into a sleep deficit, the specialist recommends getting up at the same time as usual, even if it means going to bed earlier the next day. “It’s more physiological than forcing awakenings”.
- We would not all be equal in the face of the time change: is this true?
Yes, we are not all equal when it comes to the time change. Children and the elderly are more susceptible to it. Indeed, they are accustomed to fixed hours and short sleeps. Their biological rhythm is very ritualized. Consequently, these people are destabilized on the day when it is necessary to set back the watch and the clocks by one hour. A study conducted by the European Commission in 2015 pointed out that “health can be affected by the change in the body’s biorhythm”.
Also, there are individuals who are more morning or evening. “People in the morning have a shorter clock and those in the evening, slower”, continues Armelle Rancillac. The expert debunks the received idea that “the future belongs to those who get up early”. To try to regulate themselves as well as possible, it is recommended that evening individuals expose themselves to light in the morning. And vice versa. “Exposure to light will inhibit the synthesis of melatonin, an important hormone for falling asleep,” she explains. This secretion takes place during the night and reaches its maximum between 2 a.m. and 4 a.m.
- Among the other misconceptions, there is also that of saying that changing summer time is more difficult than winter time, is this true?
In fact, there are more of us in the evening than in the morning, so it’s easier to go back an hour than to move forward. How to explain this? “It’s genetic and linked to the functioning of our internal clock. All individuals are more or less set on 24 hours, but some are on 22 or 26 hours. It is thanks to exposure to light that we will synchronize, that we will adapt our window and put it on 24 hours”, advances Armelle Rancillac. Among the effects that the change to summer time can cause: sleep disturbances, a change in appetite, a reduced capacity for work or vigilance. The switch to winter time leads to a 42% increase in road accidents in November, warns the National Interministerial Observatory for Road Safety.
- Energy drinks, tobacco… Habits to avoid if you want a good night’s sleep?
It is necessary to privilege the wearing of a blindfold, try to put yourself in calm. Among the things to watch out for: energy drink, nicotine and alcohol. “The latter is a false friend of sleep. Even if we fall asleep more easily, the latter will heat our body, which will have the effect of fragmenting sleep and therefore sleeping less well”, says the specialist. Regardless of the time change, one thing is certain: we are not all equal when it comes to sleep.