Do you know someone who loves the night? Maybe the sweet silence of 3 a.m. is appealing to them. Perhaps they work nights or study late. A Korean study found a causal relationship between being a night owl and metabolic disorders. In addition, a recent study conducted by the UK Biobank sought to determine whether there could be a connection between sleeping schedules and mortality rates, and the results might be compelling enough to make people rethink bedtime.
Sleeping by “Chronotype”
The study used a questionnaire to determine which of four sleep categories (or chronotypes) participants fell into: “definite morning” people, “moderate morning” people, “definite evening” people, or “moderate evening” people.
Of the groups, those who self-identified as “definite evening” people (night owls) appeared to be at highest risk of developing a number of different health issues, including being at a 10% higher risk for early death than people who go to bed at a more normal time and are early risers. In addition, mental health disorders, diabetes, gastrointestinal disorders, metabolic disorders, neurological disorders, and respiratory disorders were also found to be more common in night owls than in other groups.
“Moderate evening” people were found to be at a relatively increased risk for health issues, albeit lower than that of their night owl counterparts. Some of these related health issues, such as cardiovascular disease, could increase a person’s overall risk of death.
Cause or Effect?
Researchers accounted for other variables that could affect health and lifespan, such as smoking, weight, sex, age, and socioeconomic status, leaving chronotype itself as a potentially important factor. However, the exact nature of this relationship is still up for debate. While some believe "definite evening" people may face increased health risks due to simply being awake when they should be sleeping, others attribute it to the stress put on the body from trying to adapt to “normal” sleep schedules.
Many insist there are clear genetic components to chronotypes, so that some people are naturally early birds and some are naturally night owls. Some researchers believe it’s possible to retrain a person’s chronotype, whereas others believe it is, for the most part, genetically fixed. Most agree, however, that getting regular, scheduled sleep is important above all else.