Why Night Owls Die Earlier Than Early Birds

In popular sleep medicine, a distinction is often made between larks and owls, i.e., between early birds and night owls. Even if not everyone can be clearly assigned to one type or the other: our biorhythm follows its own inner clock, which is difficult to get out of sync.

Now a Finnish study shows that the chronotype of the night owl is nine percent more likely to die earlier. So is staying up late at night dangerous?

To find the answer, the researchers analyzed data from a large-scale twin study. Nearly 23,000 men and women were observed between 1981 and 2018. At the beginning, participants were asked whether they “completely” or “prefer” to see themselves as an early bird or a night person.

Based on just over 8,700 deaths, the researchers examined each group’s proportion. It turned out that night owls have a higher risk of death.

The researchers now also took into account other parameters, such as body mass index, actual sleep time and alcohol, drug and tobacco use. And it was precisely in the latter that there were deviations.

Night owls were generally younger and used more alcohol and other drugs: “There is a reciprocal relationship between the reward system and the 24-hour circadian rhythm (the body clock, editors note), and levels of alcohol and substance use correlate with prefer to stay up later in the night, i.e. in the evening.”

Translated: The reason for their increased risk of death was not that the night people stayed awake longer. The authors clarify: “Our results suggest that chronotype has little or no independent contribution to mortality.”

Instead, activities during this waking time increased their risk of death. Evening habits such as drinking and smoking contributed to shortening their lifespan. If they didn’t, owls wouldn’t die before larks.

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