Heart disease risk may be linked to bedtime consistency, study finds

A 10-year study of 3,231 Finnish adults who wore wrist sleep monitors found that irregular bedtimes were associated with about twice the risk of heart attack, stroke, heart failure hospitalization, or cardiovascular death compared with regular bedtimes. The increased risk was concentrated among people who slept under eight hours; irregular wake times did not show the same association.

A new study published in BMC Cardiovascular Disorders examined whether variation in bedtime was linked with long-term cardiovascular outcomes. Researchers followed 3,231 Finnish adults born in 1966 who wore research-grade wrist sleep monitors for seven days and later compared those data with Finland’s national health registry over a 10-year period for heart attacks, strokes, heart failure hospitalizations, and cardiovascular deaths. Experts quoted in the coverage included John La Puma, M.D., and Srihari Naidu, M.D., and the American Heart Association has recently added sleep regularity to its list of components related to heart health. The reporting highlights that bedtime timing, not just sleep length or wake time, was the focus of the analysis. Key findings: - Sample and method: 3,231 adults (born 1966) wore wrist sleep monitors for seven days; outcomes were tracked through a national registry over 10 years. - Bedtime groups: participants were categorized as regular, fairly regular (within about one hour), or irregular (up to nearly two hours difference) in bedtime. - Risk association: those with irregular bedtimes showed about a twofold higher risk of heart attack, stroke, heart failure hospitalization, or cardiovascular death after controlling for standard age- and sex-related cardiac risk factors. - Wake time: irregular wakeup times did not predict the same increased risk. - Sleep duration: the elevated risk was concentrated among people who slept less than eight hours per night. Summary: The study reports an association between irregular bedtimes and higher rates of major cardiovascular events over a decade. Undetermined at this time.