Middle-aged and older adults who are naturally more active in the evenings have poorer cardiovascular health compared to their peers, with women showing particularly strong associations, according to research published in the Journal of the American Heart Association. The study analyzed data from over 300,000 UK Biobank participants and found that self-described "definitely evening people" had a 79% higher prevalence of poor cardiovascular health scores and a 16% higher risk of heart attack or stroke over approximately 14 years compared to those without strong chronotype preferences.
Cardiovascular health was measured using the American Heart Association's Life's Essential 8 metrics, which assess diet, physical activity, smoking status, sleep quality, weight, cholesterol, blood sugar, and blood pressure. Researchers found that much of the increased risk among evening chronotypes was attributable to unhealthy behaviors, particularly nicotine use and inadequate sleep. Lead author Sina Kianersi noted that "evening people often experience circadian misalignment" and "may be more likely to have behaviors that can affect cardiovascular health, such as poorer diet quality, smoking and inadequate or irregular sleep."
The study's findings offer a pathway for risk reduction, according to experts. Kristen Knutson, who chaired the American Heart Association's 2025 statement on circadian health, emphasized that "evening types have options to improve their cardiovascular health" since the risks are "partly due to modifiable behaviors." The research suggests that targeted programs for night owls could help them improve lifestyle behaviors and reduce cardiovascular disease risk. Additional information about the American Heart Association's financial policies is available here.
While the study has limitations—including a predominantly white, healthy participant pool and self-reported chronotype data—the implications for personalized healthcare are significant. The American Heart Association scientific statement suggests considering individual chronotype when timing interventions or treatments, as "some medications or therapies work best when they align with a specific time of relevant circadian rhythms." This approach could be particularly beneficial for the approximately 8% of participants who identified as definite evening types, compared to 24% who were definite morning types and 67% with intermediate preferences.
