Switching to summer time: how to manage fatigue afterwards?

Every year, in March, we switch to summer time so we sleep one hour less. In other words, at 2 a.m., it’s finally 3 a.m.. We “lose” an hour of sleep, but we gain an hour of natural light at the end of the day.

What are the consequences of summer time on health?

The body is regulated to a rhythm called “nycthemeral”. A biological rhythm which corresponds to a 24-hour cycle, composed ofa period of day and D’a night period. During these 24 hours, different hormones are secreted in the body. “Notably melatonin (sleep hormone) whose secretion is maximal at the time of falling asleep, generally between 10 and 11 p.m. and which will be exhausted during the night so that the body can gradually wake up in the morning. Then, another hormone takes over, it is the cortisol which, conversely, is secreted when we wake upexplains Dr Catherine Lamblin, sleep doctor at the La Louvière private hospital in Lille and member of the scientific committee of the Ramsay Santé Foundation. But when we change the time arbitrarily, as is the case when we switch to daylight saving time, the hormones will take a few days to settle into this new rhythm.”

Fatigue: “It generally takes 3-4 days to cope with the summer time change”

The change to summer time is often more problematic than the change to winter time. And this for many reasons. On the one hand, it is less easy to absorb than the change to winter time, since it deprives us of an hour of sleep. On the other hand, “when switching to summer time, we shift in the opposite direction and move away from solar time and therefore from our natural sleep/wake cycle“, explains our interlocutor. In addition, we ask our body to settle on a different schedule so it will not be synchronous for a few days.

“Melatonin is generally secreted in the dark, when we perceive less and less daylight. When we switch to daylight saving time, we perceive the night later, our melatonin will be secreted later and we will want to sleep later The evening. In addition, we will have less ease getting up in the morningspecifies Dr Lamblin. It generally takes 3-4 days to fully process a time change“. Note that “evening” people will be more bothered when switching to summer time and will have more difficulty getting up in the morning. On the other hand, the switch to summer time will happen without too much trouble for early sleepers.

The ideal is toanticipate this transition to summer time. Here are 5 tips:

► Two to three days before the time change, it is advisable to go to bed slightly earlier than usual -about twenty minutes- in order to gradually shift and adapt to the new day/night cycle.

► You must not arrive at the time change with too much sleep debt. “To easily adapt to the new time, the body must not be deprived of sleep“, insists the specialist.

► Likewise, you should avoid having too irregular waking and going to bed times. Concretely, you should try to go to bed every evening at around the same time, including on weekends. If you shift yourself by staying up very late and sleeping in on weekends, you risk causing a break in rhythm on a chronobiological level and gradually disrupt your biological clock.

► It is not recommended to go to bed late on the evening of the time change so as not to further increase the sleep deficit. “Even though we deprive our body of an hour of sleep that day, we must not accumulate fatigue either. We can set a bedtime around 11 p.m. For example“, she continues.

► It is advisable to do a little physical activity on Saturday and Sunday mornings of the weekend of the time change to “tire” his body a little more and encourage him to go to bed a little earlier in the evening.

What advice to quickly get back on track?

► Listen to yourself. The day after the time change, “It would be better listen to our body and go to bed when we feel tiredeven if it is not always easy with professional or family constraints“, recognizes Dr Lamblin. It is also advisable to go to bed slightly earlier the following week the time change to help the body better regulate itself.

► Expose yourself to screens as little as possible before bedtime : “Blue light emitted by screens prevents melatonin secretion“, she explains. Above all, an eye that absorbs blue light just before sleeping sends false information to the brain which thinks while it is still in “broad daylight”. Result: falling asleep is delayed, sleep time is shorter and sleep quality is impaired.

► Do not postpone your evening meal, even if you are not hungry. It’s better to have a light dinner at the usual time than to skip a meal.

► Expose yourself to daylight in the morning and at midday during your lunch break to store sunshine: “This allows you to stay awake in the afternoon, to stimulate yourself and to be generally more fit until the end of the day“, indicates the expert. On the other hand, we avoid staying outside too long after 6 p.m., because too much light at the end of the day can delay the desire to go to bed and thus interfere with rest. For restful sleep, you also need minimize all lighting sources (screens, indicator lights on electronic devices, urban lighting, night lights, etc.) which can interrupt or fragment sleep.

Thanks to Dr Catherine Lamblin, sleep doctor at the La Louvière private hospital in Lille and member of the scientific committee of the Ramsay Santé Foundation.