Staying up late to binge a favorite TV show or go out with friends can be one of life’s simple pleasures. But being a habitual night owl—especially if you are a woman—may be putting your heart at risk, new research suggests.
In a study of more than 320,000 adults, researchers found that participants who described themselves as “definitely an ‘evening’ person” were about 16 percent more at risk of having a heart attack or stroke compared with those who didn’t report a strong bedtime preference.
The study was partially funded by the American Heart Association (AHA) and published on Wednesday in the Journal of the American Heart Association.
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The findings jibe with existing AHA guidance that people should aim to get a good night’s sleep to reduce the risk of cardiovascular disease. But it wasn’t clear how “circadian misalignment”—the mismatch between the body’s internal clock and the times at which people actually go to sleep and wake up—might affect heart heath.
Such a mismatch can throw off how our brain responds to reward signals—and that could lead to people engaging in riskier behaviors, the researchers say. “Evening people may be more likely to have behaviors that can affect cardiovascular health, such as poorer diet quality, smoking and inadequate or irregular sleep,” said Sina Kianersi, a research fellow at Brigham and Women’s Hospital and a co-author of the paper, in a statement.
Kianersi and his colleagues found that night owls were more likely to score poorly on the AHA’s “Life’s Essential 8” questionnaire, which looks at a series of eight health and lifestyle metrics, including exercise, smoking, blood pressure and blood sugar. The “evening people” tended to score low because they were more likely to smoke (or live with a smoker) and get inadequate sleep, according to the findings.
If you are a night owl, have courage: the research points to steps you can take to avoid additional heart risks, said Kristen Knutson, an associate professor at Northwestern University’s Feinberg School of Medicine, who was not involved in the study, in the same statement. “These findings show that the higher heart disease risks among evening types are partly due to modifiable behaviors such as smoking and sleep,” she said.
“Evening types aren’t inherently less healthy,” Knutson said, “but they face challenges that make it particularly important for them to maintain a healthy lifestyle.”