Night Owls & Heart Health: Women at Higher Risk

For many, the debate between being a “night owl” or an “early bird” is a matter of personal preference. However, new research suggests that when we are most active during the day may have significant implications for long-term heart health, particularly as we age, and the risks appear to be greater for women.

Study Reveals Link Between Activity Timing and Heart Health

Researchers examining data from over 300,000 adults with an average age of 57, enrolled in the UK Biobank, found a correlation between being most active in the evening and poorer cardiovascular health. The study, published in the Journal of the American Heart Association, utilized the American Heart Association’s Life’s Essential 8™ metrics to evaluate heart health, considering factors like diet, physical activity, smoking, sleep, weight, cholesterol, blood sugar, and blood pressure.

How Chronotypes Were Defined

Participants self-identified their daily patterns, falling into three groups: approximately 8% were “definitely evening people” (typically active late into the night, such as 2 a.m.), 24% were “definitely morning people” (rising and active early, like 9 p.m.), and 67% were categorized as having an “intermediate” chronotype.

The analysis revealed that individuals identified as “evening people” were 79% more likely to have a poor cardiovascular health score compared to those in the intermediate group. They also faced a 16% higher risk of experiencing a heart attack or stroke over a median follow-up period of 14 years. Notably, this association between evening chronotype and reduced heart health was more pronounced in women than in men.

Lifestyle Factors Play a Key Role

Researchers found that much of the increased heart disease risk among “evening people” could be attributed to lifestyle habits. Specifically, night owls were more likely to have lower-quality diets, insufficient sleep, and higher rates of smoking. In contrast, “morning people” showed a 5% lower prevalence of poor cardiovascular health scores compared to those with intermediate chronotypes.

According to lead study author Sina Kianersi, Ph.D., D.V.M., “Evening people” often experience “circadian misalignment,” where their internal body clock doesn’t align with the natural day-night cycle or their daily schedules. This misalignment may contribute to unhealthy behaviors impacting cardiovascular health.

Hope for Night Owls

Despite these findings, experts emphasize that the increased risk isn’t inevitable. Kristen Knutson, Ph.D., FAHA, noted that the higher risks among evening types are linked to behaviors that can be changed, such as smoking and sleep patterns. She stated that evening types “aren’t inherently less healthy, but they face challenges that make it particularly important for them to maintain a healthy lifestyle.” The American Heart Association also suggests that treatment and lifestyle interventions should consider an individual’s chronotype for optimal effectiveness.

Frequently Asked Questions

What is a chronotype?

A chronotype describes a person’s natural preference for sleep and wake timing. Participants in the study categorized themselves as “definitely evening people,” “definitely morning people,” or having an “intermediate” chronotype.

What are the Life’s Essential 8™ metrics?

Life’s Essential 8™ is a framework used to evaluate cardiovascular health, looking at behaviors and health factors including diet, physical activity, smoking, sleep, weight, cholesterol, blood sugar, and blood pressure.

Could tailoring treatment to chronotype improve health outcomes?

Yes, the American Heart Association recommends considering chronotype when planning treatment or lifestyle interventions, as some medications or therapies may be more effective when aligned with an individual’s natural circadian rhythms.

As research continues, it’s possible that a deeper understanding of chronotypes will lead to more personalized approaches to preventative care and treatment, potentially mitigating the cardiovascular risks associated with being a night owl.