A recent study suggests that individuals who prefer staying up late, often referred to as “night owls,” face a higher likelihood of adopting unhealthy lifestyle behaviors and an elevated risk of developing Type 2 diabetes compared to “early birds.”
The term “night owl” does not merely denote those who stay up late for social reasons but relates to one’s circadian preference, a partially genetically determined natural body clock. This means that night owls have a distinct biological predisposition to stay awake later than individuals who naturally wake up early and retire early.
The study, which analyzed data from over 60,000 female nurses participating in the Nurses’ Health Study II, discovered that night owls exhibited a greater tendency to follow unhealthy diets, engage in less physical activity, have a higher body mass index (BMI), sleep fewer hours, and smoke cigarettes when compared to early birds. These findings were reported in the Annals of Internal Medicine.
Furthermore, the research indicated that night owls were more susceptible to developing diabetes, with an approximately 19% increased risk, even after adjusting for other contributing factors. This risk factor was deemed significant by the study’s senior author, Tianyi Huang, an assistant professor of medicine at Harvard Medical School and an associate epidemiologist at Brigham and Women’s Hospital in Boston.
Among the women in the study, 11% identified as night owls, while 35% considered themselves early birds. The remaining half did not strongly align with either morning or evening preferences.
This study adds to the growing body of evidence linking evening chronotypes—those who feel more energetic at night—to potential health risks. Previous research has already associated being a night owl with conditions such as obesity and heart disease.
Huang hypothesizes that the increased diabetes risk among night owls may be attributed to their chronotype being out of sync with their daily routines, particularly their work schedules. Many night owls find themselves retiring late at night but having to rise early for work. Interestingly, the study did not find an increased diabetes risk among evening chronotypes who engaged in night shift work.
Marie-Pierre St-Onge, director of the Center of Excellence for Sleep and Circadian Research at Columbia University Vagelos College of Physicians and Surgeons, suggests that individuals with late-night body clocks should be cautious about their lifestyle habits if they cannot find work that aligns with their natural rhythms. Healthy eating, proper sleep, and regular physical activity can help mitigate some of the risks associated with being a night owl.
While some night owls may temporarily adjust their sleep patterns due to life events like parenthood, they often revert to their natural tendencies, as changing one’s chronotype can be challenging due to strong genetic influences.
St-Onge speculates that evening chronotypes may have evolved as a necessity to maintain vigilance during nighttime hours when others could not, ensuring continuous safety. However, it’s essential to note that this study does not conclusively prove that being an evening chronotype directly causes an increased risk of diabetes, according to sleep specialist Dr. James McGuirk, an assistant professor of neurology at Vanderbilt University Medical Center in Nashville, Tennessee. McGuirk emphasizes that the study’s participants were predominantly white women, suggesting a need for further research to broaden its scope and explore these findings in more diverse populations.