Staying Up Late Could Be Bad for Your Heart

Burning the midnight oil might not just make mornings rough—it could also be tied to worse heart health, especially for women, according to a new study. Researchers analyzed data from nearly 323,000 adults in the UK Biobank and found that people who described themselves as "evening" types were more likely to have poorer cardiovascular health than those who considered themselves a morning person, or even someone in between, per NBC News. About 8% of the study's subjects considered themselves night owls, while 24% said they were early birds. The majority, 67%, claimed that middle "intermediate" ground, per HealthDay.

The research found that night owls had a 79% higher prevalence of poor heart health compared with people in the intermediate group. Early risers, meanwhile, had a slightly lower prevalence of poor heart health—about 5% lower than the intermediates. Over roughly 14 years of follow-up, self-identified night owls also had a 16% higher risk of heart attack or stroke than the intermediate group; early birds didn't face an elevated risk. The link appeared stronger in women, though the reasons aren't yet clear.

Experts stress that the results don't mean late sleepers are doomed. The increased risks were described as modest, and the study, published in the Journal of the American Heart Association, was observational, based largely on self-reported sleep patterns in mostly white, middle-aged, and older adults at a single point in time. Also, "these findings show that the higher heart disease risks among evening types are partly due to modifiable behaviors such as smoking and sleep. Therefore, evening types have options to improve their cardiovascular health," sleep expert Dr. Kristen Knutson, who wasn't involved in the study, says in a release.

Still, researchers say the findings add to evidence that misalignment between our internal clocks and daily schedules can affect cardiometabolic health. Doctors say many of the habits linked to poorer heart scores in night owls are changeable: Individuals should aim for seven to eight hours of sleep, quit smoking, get more activity in during daylight hours, cut off caffeine well before bedtime, and manage light exposure—bright in the morning, dim in the evening—to support a more stable sleep-wake rhythm.