Night-owl lifestyle comes with health penalties

Researchers have found that staying up late has knock-on negative side-effects.

Researchers on a major Finnish study spanning 37 years have uncovered a striking pattern showing that people who go to bed late increase their risk of dying early compared with those who go to bed at an earlier hour.

This confirms the results of previous studies that have similarly attributed a higher mortality risk to people who categorise themselves as ‘night owls’. But the new study also offers reasons why this pattern occurs.

In the study, the researchers analysed data from 22,976 Finnish adult twins that were observed between 1981 and 2018. Of these twins, 42.9% of the participants identified themselves as “night owls” or “night owls to some extent.”

Over the 37 years of the study, 8728 of the test subjects died. By reviewing Finnish death records, the researchers could calculate that the overall risk of dying from any cause was 9% higher for those who described themselves as definite night owls compared to those who described themselves as definite early risers.

However, the researchers say it would be incorrect to attribute this specifically to the sleep rhythm. According to the researchers’ analyses, those on night-owl hours tended more towards risky behaviour than early risers, and were in particular more likely to drink and smoke.

When the researchers looked specifically at night owls who were non-smokers and who did not drink much alcohol, those test subjects had no increased risk of premature death. In the analysis, the researchers also adjusted for factors such as education, BMI, and sleep habits. Their results suggest that sleep patterns may be less important in themselves than previously believed; it is behaviour that has a greater effect on longterm health.