A recently conducted study spanning over 37 years and involving nearly 23,000 Finnish twins has shed light on the impact of lifestyle choices on health. Surprisingly, the study found that decisions such as smoking and drinking had a greater influence on health than whether a person identified as a ‘morning’ or ‘evening’ person. However, the research did reveal a slightly increased risk of mortality among individuals who identified as evening types compared to morning types. Interestingly, staying up late at night did not significantly affect the lifespan of “night owls.”

The lead author of the study, Christer Hublin from the Finnish Institute of Occupational Health in Helsinki, emphasized that the findings suggest that a person’s chronotype has little to no independent contribution to their risk of mortality. The increased risk associated with being an evening person seems to be primarily attributable to a higher consumption of tobacco and alcohol, when compared to those who are clearly morning people.

Co-led by Jaakko Kaprio from the Finnish Twin Cohort study at the University of Helsinki, the research followed 22,976 men and women aged 24 years from 1981 to 2018. The study took various factors into account, including education, daily alcohol consumption, smoking habits, body mass index (BMI), and sleep duration. The findings have been published in the journal Chronobiology International. Participants were initially asked to categorize themselves into four groups: ‘I am clearly a morning person,’ ‘I am somewhat a morning person,’ ‘I am clearly an evening person,’ or ‘I am somewhat an evening person.’ In 2018, when the study concluded, the researchers checked nationwide registers to gather data on participant deaths.

The results indicated that compared to morning types (13,123 participants), individuals who identified as night owls (9,853 participants) were younger and had higher rates of drinking and smoking. Furthermore, those who were classified as ‘definite’ evening people (2,262 participants) were less likely to report getting 8 hours of sleep. Out of the total participants, 8,728 had passed away by 2018. The study revealed that ‘definite’ night owls had a 9% higher chance of dying from any cause compared to early birds, but the primary factors behind these deaths were smoking and alcohol consumption rather than chronotype.

Interestingly, the researchers found that non-smokers did not face an increased risk of mortality. The causes of death related to alcohol included alcohol-related diseases as well as accidental alcohol poisoning. Among the twins in the study, 7,591 identified themselves as ‘somewhat’ evening types, while 2,262 identified as ‘definite’ evening types. In contrast, 6,354 and 6,769 individuals identified themselves as ‘somewhat’ and ‘definite’ morning types, respectively.