Chronotype is the phenotypic expression of an individual’s innate circadian rhythm, the part of the day between morning and evening that is preferred for daily activities. The later chronotype (evening type) is associated with an evening preference for activities and a later sleep timing.
According to recent studies, staying up late does not affect how long ‘night owls live. However, data on almost 23,000 twins reveals that evening types have a slightly higher risk of passing away than morning types, primarily tied to smoking and alcohol consumption.
According to a study conducted in Finland over 37 years, lifestyle should be considered.
This is when examining how chronotype—the body’s innate propensity to go to sleep at particular times—affects health.
Dr. Christer Hublin, from the Finnish Institute of Occupational Health in Helsinki, said, “Our findings suggest that there is little or no independent contribution of chronotype to mortality. In addition, the increased risk of mortality associated with being a clearly ‘evening’ person is mainly accounted for by a larger consumption of tobacco and alcohol. This is compared to those who are clearly ‘morning’ persons.”
There is mounting evidence that night shift work, sleep duration, and quality all impact health. Previous research has connected night owls with an increased risk of disease, particularly cardiac issues.
In this study, scientists analyzed some things that were not measured – alcohol consumption and the amount people smoked, rather than just status. They followed 22,976 men and women aged 24 years from 1981 to 2018.
The twins were given four options to choose from at the outset of the study: “I am a morning person,” “I am to some extent a morning person,” “I am an evening person,” and “I am to some extent an evening person.”
In 2018, the researchers checked in on the participants to see if any had passed away. They used information from national registrations as the basis for this. The authors considered the following factors: education level, daily alcohol intake, status and amount of smoking, BMI, and amount of sleep.
According to the findings, 2,262 and 7,591 of the twins identified as “definite” and “to some extent” evening types. There were 6,354 and 6,769-morning types, respectively.
Night owls were younger and smoked/drank more than morning people. Those who are definite night owls were also less likely to claim to receive 8 hours of sleep. 8,728 participants had passed away by 2018, and night owls had a 9% higher risk of passing away from any cause than early birds.
The investigation discovered that chronotype was not the major cause of these deaths, but instead alcohol and smoking. This result was clear because nonsmokers did not face an elevated mortality risk.
In addition to alcohol-related illnesses, unintentional alcohol poisoning was one of the causes of alcohol-related deaths.
Dr. Jaakko Kaprio, from the Finnish Twin Cohort study at the University of Helsinki, said, “They were more able to relate their findings to society. Their participants’ health differed from the general population whereas the UK Biobank’s were healthier than average.”
“They highlight the access to comprehensive data on lifestyle factors as a strength of their research. However, the findings were based on self-reported data from asking one question.”
Journal Reference:
- Christer Hublin and Jaakko Kaprio. Chronotype and mortality – a 37-year follow-up study in Finnish adults. Chronobiology International. DOI: 10.1080/07420528.2023.2215342