Nachteule oder Frühaufsteher: Studie zeigt, dass Schlafkategorien nicht so einfach sind. Wissenschaftler identifizieren 5 biologische Schlaf-Wach-Profile (2 Frühaufsteher, 3 Nachteulengruppen), die mit unterschiedlichen Gesundheits- und Verhaltensmustern verknüpft sind, und helfen zu erklären, warum Schlafpläne Menschen unterschiedlich beeinflussen.

**Night owl or early bird? Study finds sleep categories aren’t that simple**

**Scientists identify five biological sleep-wake profiles linked to different health and behaviour patterns, helping explain why sleep schedules affect people differently**

The familiar labels “night owl” and “early bird,” long used in sleep research, don’t fully capture the diversity of human internal clocks, a new study has found.

The McGill University-led study published in Nature Communications found the two sleep-wake patterns, called chronotypes, contain a total of five distinct biological subtypes, each associated with different patterns of behaviour and health.

A chronotype is based on the parts of a 24-hour period when a person naturally feels most alert or ready to sleep. Previous research has linked late chronotypes to worse health outcomes, but results have often been inconsistent. The new findings help explain why, the authors said.

“Rather than asking whether night owls are more at risk, the better question may be which night owls are more vulnerable, and why,” said lead author Le Zhou, a PhD student in McGill’s Integrated Program in Neuroscience.

A broader spectrum of sleep types
Using AI, researchers combined brain imaging with questionnaires and medical records from more than 27,000 adults in the U.K. Biobank. The work drew on computational resources from the McConnell Brain Imaging Centre, and contributions from collaborators at Université de Montréal and the University of Oxford.

**Their analysis revealed three types of night owls and two types of early birds.**

One group of early birds had the fewest health problems overall, while the other was closely tied to depression.

As for night owls, one performed better than other groups in cognitive tests but had more emotional-regulation challenges. Another group showed a tendency toward risk-taking behaviours and cardiovascular problems, while a third was more likely to have depression, smoke and face higher risks of heart disease.

For those interested, here’s the link to the peer reviewed journal article:

https://www.nature.com/articles/s41467-025-66784-8