McGill study links sleep profiles to health risks for night owls, early birds

A new study from McGill University looks at night owls and early birds — and how people’s sleep preferences can impact their health.

Scientists identified five sleep–wake profiles, including three kinds of night owls and two kinds of early birds, that are linked to behaviour patterns.

Lead author Le Zhou, a PhD student in McGill’s Integrated Program in Neuroscience, said there are high-performing night owls, but that they also face challenges with emotional regulation.

“They are easier to get angry and have more [addictive tendencies,] such as smoking, drinking, and substance use,” he explained, adding that underlying issues like depression or anxiety can also impact sleep patterns, such as not being able to sleep.

Additionally, he said lifestyle choices also play a part for night owls. “Cardiovascular disease and depression. And they don’t like physical activity.”

Using artificial intelligence (AI), researchers combined brain imaging with questionnaires and medical records from more than 27,000 adults in the U.K. Biobank.

The findings indicate that early birds have different health issues.

“Very stable lifestyles. They don’t like high risk behaviours. And they drink less, they don’t smoke. They have a healthy profile,” Zhou explained.

The other early-bird subset has a similar health profile but is deemed vulnerable to anxiety and depression.

“Also linked to social traumatic experiences such as sexual assault,” he said, adding that a sleep profile is like a personality trait.

Zhou said understanding a person’s sleep style can help them know what works best for them and guide health professionals on what supports could help them rest day or night.