Scientists have studied "night owls". The results show a 1.7 times greater risk

Chronotype is the natural, biological rhythm of sleep and wakefulness, determining what time of day a person is most active and productive. There are three main types: morning, intermediate and evening. "Owls" prefer later hours of activity, while "larks" function best early in the morning.

According to scientists from the University of Oulu, these differences are not just a matter of personal habits, but have a strong genetic basis and are an innate biological feature that remains constant throughout life.

Researchers analyzed data from a population-based study dating back to 1966, covering 96 percent. all people born in the two northern provinces of Finland. Participants were classified according to chronotype at the age of approximately 45 years, and then their professional and health situation was followed for the next 12 years.

The group of people with an evening chronotype included 253 men and 381 women, while the "larks" group included 1,182 men and 1,355 women. The remaining participants were assigned to the intermediate type. These data were combined with information from Finnish national registers on work and pension benefits.

The analysis showed that people classified as having an evening chronotype at the age of 46 were 1.7 times more likely to receive a disability pension over the next 12 years than their peers with a morning chronotype. Importantly, this relationship persisted even after taking into account socio-economic factors, such as the level of education and the type of work performed.

Scientists emphasize that in Finland, a disability pension is granted only after long-term and serious deterioration of health. This indicates that the poorer health of "owls" is the main reason for the more frequent early retirement in this group.

The research team notes that people with an evening chronotype make up a significant portion of the population, and their ability to continue working until retirement age may impact the stability of economies.

The authors emphasize that the study was observational, which means that it does not allow for clear conclusions to be drawn regarding cause-and-effect relationships. However, its strength was its wide representativeness and long observation period of participants from various sectors of the economy and professions.