The Nuance

The Dawning Truth about Night Owls

Why staying up late is linked to health problems

Markham Heid
Published in
4 min readJul 5, 2019
Photo: Green Apple Studio/Getty

DDuring his time in the Oval Office, Barack Obama was a self-proclaimed “night guy” who tended to stay up well past midnight despite his early morning duties. His predecessor, George W. Bush, was usually in bed by 10 and often started his workday well before seven a.m.

New research suggests Bush and other “morning larks” may have fewer health risks than their “night owl” counterparts.

Last year, a study found people who considered themselves to be “evening types,” loosely defined as those who prefer to stay up and rise late, were at greater risk than morning types for psychological disorders, diabetes, neurological disorders, gut disorders, and even death. More research in this vein also suggests that evening types are at greater risk for heart disease.

“If people are always having to adhere to a schedule they’re not suited to, that may create health problems,” Wulff says.

And a study published last week in The BMJ medical journal found that in women, being a “morning person” is associated with a lower risk for breast cancer. The U.K. study team analyzed genetic data, sleep questionnaires, and breast cancer incidence reports collected from hundreds of thousands of women. Using a variety of analytic techniques, they found “consistent evidence” that women who were early to rise and early to bed were less likely to develop breast cancer than women who stayed up and slept in late.

The study authors acknowledged that their findings had limitations — first and foremost that the women in the study self-reported their sleep-wake habits and preferences, and therefore were subject to error. But their study’s findings aren’t the first to link morning preferences with a health benefit.

FFor a while now, researchers have understood that human beings are equipped with built-in “clock genes” that exist in every cell in the body, and that are active or inactive at regular intervals throughout the day. These clock genes, in conjunction with environmental cues such as daytime sun exposure, help set the body’s internal circadian…



Markham Heid

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.