Some bad news for those who like to stay up late. A six-and-a-half-year study on the sleep habits of almost half a million people in the UK suggests that night owls are at a higher risk of early death than morning people. Though the study didn't examine the cause of this correlation, researchers suspect the problem doesn't actually have to do with sleeping in, specifically. The study published Thursday in the journal Chronobiology instead cites "circadian misalignment," per Live Science. "We think the problem is really when the night owl tries to live in a morning-lark world," study author Kristen Knutson of Northwestern University tells the Los Angeles Times. "They want to be up late but they have to be up early for work and so the time that they're doing things, like waking up or eating, is not at the correct time for them."
After compiling data on 433,268 people aged 38 to 73, researchers divided them into four groups: definite morning types (early risers), moderate morning types, moderate evening types, and definite evening types (night owls). They found night owls were 10% more likely to have died during the study period than early risers, even though participants in the two groups reported getting roughly the same amount of sleep. Night owls were also more prone to diabetes, psychological disorders, and neurological disorders, per a release. "This is a public health issue that can no longer be ignored," says study co-author Malcolm von Schantz of the University of Surrey. He suggests employers be encouraged to allow night owls to start later, when possible. (More sleep could mean more nightmares.)