The clock is an hour ahead again this weekend. For some people, this leads to sleep deprivation every year and can even be more annoying than jet lag. Seven questions about the differences between the jet lag and the summer time effect to chronobiologist Marijke Gordijn.
An hour less sleep is nothing compared to a real jet lag?
"Shifting an hour with time does not seem like much, but with jet lag it is often easier for your internal clock to adjust than during summer time. This is because during a flight not only the time, but also the light -dark cycle changes at destination. "
And not in summer time?
"No. We have to get up an hour earlier than the day before. According to your internal clock, it is still too early to get up. This is confirmed by the fact that it is still dark outside. We also call this 'social jet lag'."
How does that work?
"Our internal rhythm is slightly behind the 24-hour daily rhythm. That is not a problem, because the main clock is always set by external stimuli, including daylight. Daylight in the morning ensures that all kinds of signals are sent to the brain where different processes are underway. "
"This way we are able to keep our main clock in line with the natural alternation of light and dark and we can fall asleep and wake up in time."
What happens if we disrupt that rhythm?
"If we fly intercontinental, the main clock is in order fairly quickly: it starts running, depending on the number of time zones you cross, after a day or so again with the rhythm of the world around you."
"The jet lag complaints are caused by the fact that the smaller clocks - which indicate the size in our muscles, liver and intestines - and our main clock are no longer properly aligned. Some take much longer to get back in line, others shift faster . "
And at summer time?
"In summer time, the main clock also has trouble adjusting because it is not corrected by daylight. Some people can suffer from it for up to four weeks. Especially late types, the 'evening people', have difficulty adapting. They sleep in any case too few weeks by changing the clock, possibly even all summer. "
Who else is affected? Children and the elderly?
"Children live much more to their own internal clock instead of the alarm clock or a watch. That they also suffer from 'social jet lag' is because they have to keep up with the rhythm. They do not understand that they suddenly go to bed an hour earlier have to go while they are not yet asleep or wake up to get out. But basically they are flexible. "
"Older people can also suffer from summer time. Jet lag, by the way, and even more often from shift work. Although the image of older people is that they often doze off in the afternoon, healthy older people cannot sleep as well during the day. This means that for example, they cannot catch up on sleep after working one night. "
How bad is that, actually, a little sleep deprived?
"Whether you suffer from it much or little, the disturbances that arise in the synchronization of the internal rhythm will disrupt all kinds of hormones and body processes and disturb our sleep for a long time. This can lead to health problems, such as obesity and diabetes, intestinal and upset stomach and cardiovascular disease. "
Summer time: this is how you do it
- Grab as much light as possible in the morning and also go outside regularly during the day
- Reduce light exposure in the evening
- Go to bed on time. Many problems arise because we stay up late at night and then have to get up earlier than usual because of summer time