It’s not just morning larks and night owls. There are five unique types of sleepers out there, according to new research, and which kind you are is tied to your health and lifestyle.
These “hidden subgroups” among early risers and late sleepers are each associated with distinct patterns of human behavior and health.
One group of early birds, for instance, has the fewest health problems overall, while the other group has higher rates of depression. Night owls, meanwhile, show even greater diversity of cycles and outcomes.
“In today’s digital and post-pandemic era, sleep patterns are more diverse than ever,” says Le Zhou, a neuroscience grad student from McGill University in Canada.
“Understanding this biological diversity could eventually help inform more personalized approaches to sleep, work schedules, and mental health support.”
Early birds and night owls are the best-known ‘chronotypes‘ – profiles that describe when during the day a person is most alert or sleepy. For years now, some scientists have argued that there are many more than just two chronotypes.
Scientists have previously categorized our 24-hour body clocks into multiple sleep patterns with associated health, psychological, and lifestyle outcomes, but the specific chronotypes identified in this study are new.
The researchers analyzed the health data and self-reported sleep patterns of 27,030 UK Biobank adults in mid- to late-life, revealing two early bird subtypes and three night owl groups.
Similar subtypes emerged when the researchers applied their model to a second cohort of more than 10,000 US teenagers.
Subtype 1 is the first of the night owls, and it is associated with risky lifestyle behaviors, difficulties in emotional regulation, faster reaction times, and better cognitive performance than in early birds.
Subtype 2 is a night owl pattern that is not so enviable. It is linked to depression, smoking, and higher cardiovascular risk. Those that fall into this subtype have lower physical activity, have decreased white matter integrity in their brains, and are more likely to use antidepressant drugs.
Subtype 3 is a ‘morningness’ pattern with fewer health issues. Sleepers that belong to this subtype tend not to smoke, rarely drink alcohol, and engage in fewer risky behaviors. They exhibit higher anxiety, but generally have fewer emotional regulation issues.
Subtype 4 is another early-bird chronotype and tends to include more females. The category is linked to depressive symptoms and antidepressant drug prescriptions.
Subtype 5 is the final night owl group and is more male-dominated. It’s associated with increased intake of alcohol, cigarettes, and cannabis, and higher cardiovascular risks and prostate diseases.
Related: Massive Study Links 6 Sleep Traits to Risk of 172 Diseases
“It may become increasingly evident that our internal sleep phasing system… ties into many more facets of daily life than previously assumed,” the research team concludes.
The study was published in Nature Communications.