Late risers suffer from chronic jet lag
In the past, late risers were laughed at as lazybones. Today, they increasingly receive backing from science - from the chronobiologists. The chronobiologists want to find out why our sleep patterns are different. And they want to enlighten about the consequences of ignoring the inner clock permanently.
In a recent study, a research team led by Professor Till Roenneberg from the Center for Chronobiology of Ludwig Maximilian University (LMU) Munich, found that behavior against the internal clock leads to a chronic form of jet lag.
What significance does the internal clock have?
Whether someone is early or late risers depends on certain genes whose function is influenced by the light. The light sets our internal clock to the day and night rhythm. As we spend less and less time outdoors, our internal clock is increasingly having problems adjusting properly.
Even on cloudy days we get 16 times more light outdoors than in the office or in the apartment. On sunny days it is even 200 times more. The weaker the light, the later the clock of most people. It's like we're constantly living in the dark.
Which type of sleep am I?
If the human being would focus exclusively on his or her own internal clock, the average sleep time would be between 0.15 and 8.15 o'clock - that was the opinion of the Center for Chronobiology of the LMU. So that's the normal type. Two out of three people are normal or late types, says Thomas Kantermann from the research team of the Center for Chronobiology.
That is, the greater part of the population would like to get up at 8.15, or later. However, as our work and school hours are more suited to the minority of early risers ("larks"), the normal and late types ("owls") often do not do justice to their inner clock.
What consequences does life have for the internal clock?
The later the chronotype, the harder it is to adhere to social schedules. "Owls show the biggest difference between their sleep times on work days and on days off," explains chronobiologist Till Roenneberg. He speaks of a "social jetlag".
"Social jet lag can have far-reaching consequences for the health and performance of those affected, and is similar to the jet lag that we experience after traveling through time zones, but it usually accompanies those affected for a lifetime," says Roenneberg. The biological clock and the social clock are in constant conflict. Many owls report low sleep quality and daytime fatigue.
And that has consequences: Roenneberg interviewed 500 subjects about their sleeping habits and the consumption of nicotine and alcohol. The result: "The stronger the social jet lag, the more likely individuals are to seek stimulants," says Roenneberg.
By the way, not only owls suffer from social jetlag. Even larks can be affected if, for example, they celebrate too long with the owls at the weekend and still wake up early the next day because of their inner clock and thus get too little sleep.
How can I influence my sleep?
Chronobiologists like Roenneberg demand that school and working hours be more adapted to the internal clock.
The alternative: one can try to influence the internal clock. If you do not get tired in the evening, you should - if possible - increasingly go outside in the morning and at noon and face the light. In the afternoon and evening the owls should avoid bright light.
Thomas Kantermann advises to go to bed earlier during the week and also on weekends and set the alarm clock for sunrise time in order to try to reprogram the inner clock in the long term. The alarm clock would ring but also on Sunday morning at 6 clock or earlier - not a nice idea for owls.
The sleep experts:
Professor Till Roenneberg© LMU
Further information about sleep can be found in our sleep series.