Night owls have a slightly higher risk of developing unhealthy habits and may possibly die earlier than those who rise early, according to a new study.
Finnish researchers analyzed data from more than 20,000 people who took a survey in 1981 about their sleep habits, according to the study published Thursday in the peer-reviewed journal Chronobiology International.
In the survey, about 29% reported they were morning people, nearly 28% reported being “somewhat” morning people, 33% reported being “somewhat” evening people, and nearly 10% reported being evening people.
For the new study, researchers looked at death records of a subset (8,728 participants) of the original study. After adjusting the data to account for educational level, use of alcohol, smoking, the level of body mass, and sleep duration, the study found that being a night owl increased the risk of an early death by about 9% compared with morning types, who are often called early birds.
Study authors found people who were self-described night owls were more likely to die younger compared with morning people, even after adjusting for factors like age, sex, ethnicity, body mass index, sleep duration, socioeconomic status and health problems.
Mortality risk increased by 21% in people who were evening types and 9% for those who were “somewhat.”
But that increased risk essentially disappeared once researchers accounted for smoking and drinking. They discovered mortality risk in night owls was mainly tied to smoking and alcohol; deaths from alcohol-related diseases and poisonings were seen more often in the evening type group.
A 2022 study found night owls were more sedentary, had lower aerobic fitness levels, and burned less fat at rest and while active than early birds.
Night owls were also more likely to be insulin-resistant, meaning their muscles required more insulin to be able to get the energy they need, the study showed.