Is More Sleep Better for Cardiovascular Health? Unveiling Risks of Long Sleep Duration and the Protective Role of the Mediterranean Diet

Highlight

• Long sleep duration (≥8 hours) is associated with a higher risk of major cardiovascular events (MACE) in patients with coronary heart disease (CHD).
• The risk of cardiovascular recurrence is particularly pronounced when accompanied by a low-fat diet.
• Long-term adherence to a Mediterranean diet may mitigate the increased cardiovascular risk linked to long sleep duration.
• Sleep duration should be considered an important factor in cardiovascular risk assessment and management.

Study Background and Disease Burden

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, with coronary heart disease (CHD) as a primary contributor. Lifestyle factors such as diet and sleep are increasingly recognized as modifiable determinants of cardiovascular risk. Although optimal sleep duration is traditionally considered beneficial for overall health, emerging evidence indicates a complex relationship between sleep length and cardiovascular outcomes. Both short and long sleep durations have been implicated in adverse health events, but the impact of long sleep duration in patients with established CHD requires further elucidation. This study from the Coronary Diet Intervention with Olive Oil and Cardiovascular Prevention (CORDIOPREV) trial explores the combined influence of sleep duration and diet on cardiovascular recurrence, offering insight into tailored lifestyle interventions to reduce major cardiovascular events (MACE) in this high-risk population.

Study Design

This prospective cohort study involved 952 participants diagnosed with CHD, enrolled in the CORDIOPREV study (NCT00924937). Sleep duration was self-reported using the Minnesota Leisure-Time Physical Activity questionnaire administered over a 7-year follow-up period. Participants were categorized into three groups based on nightly sleep duration: short sleep (≤6 hours), reference sleep (>6 to <8 hours), and long sleep (≥8 hours). Subjects were further randomized to receive dietary interventions with either a Mediterranean diet, rich in olive oil and vegetables, or a low-fat diet. The primary endpoint was the incidence of major cardiovascular events (MACE), comprising myocardial infarction, coronary revascularization procedures, ischemic stroke, peripheral artery disease, and cardiovascular mortality. Cox proportional hazards models adjusted for potential confounders assessed the association between sleep duration, diet, and cardiovascular outcomes.

Key Findings

During the study, 189 participants experienced MACE, distributed as follows: 18.1% in the reference sleep group, 17.7% in the short sleep group, and 29% in the long sleep group. Statistical analysis revealed that long sleep duration was significantly associated with increased risk of MACE compared to both the reference and short sleep groups (log-rank p < 0.01, hazard ratio [HR]: 1.59; 95% confidence interval [CI]: 1.12–2.26).

Notably, the subgroup analysis stratified by diet revealed divergent effects:
– Participants adhering to a low-fat diet and reporting long sleep duration had an even higher MACE risk (HR: 1.74; 95% CI: 1.11–2.73).
– Conversely, those on a Mediterranean diet with long sleep duration showed no significant increase in cardiovascular risk (HR: 1.35; 95% CI: 0.76–2.41), suggesting a cardioprotective modulation by this dietary pattern.

The Mediterranean diet, characterized by high intake of monounsaturated fats, fruits, vegetables, nuts, and moderate red wine consumption, may counteract the adverse cardiovascular impacts associated with prolonged sleep, potentially through anti-inflammatory and endothelial function enhancing mechanisms.

Expert Commentary

This investigation underscores the nuanced relationship between sleep and cardiovascular risk in the setting of secondary prevention. While prior studies have often focused on short sleep duration and its detrimental effects, this work highlights that excessively long sleep (>8 hours) may also confer increased cardiovascular risk. The observed protective effect of the Mediterranean diet aligns with current guidelines advocating its adoption for CHD management.

Limitations include reliance on self-reported sleep measures, which are subject to recall bias, and lack of objective sleep quality assessments such as polysomnography or actigraphy. Additionally, the directionality of the association remains to be fully clarified, as long sleep could be a marker of underlying ill health or sleep disorders rather than a direct risk factor. Future research should explore the mechanistic pathways linking prolonged sleep, diet, and cardiovascular pathology.

Conclusion

In patients with established coronary heart disease, a long sleep duration pattern (≥8 hours per night) is associated with a significantly increased risk of major cardiovascular events. Importantly, this risk is exacerbated in those consuming a low-fat diet but may be mitigated by long-term adherence to a Mediterranean diet. These findings reinforce the necessity of incorporating sleep duration assessment into cardiovascular risk stratification and emphasize the therapeutic value of comprehensive lifestyle modification encompassing both diet and sleep habits. Clinicians should counsel patients on optimizing sleep duration alongside dietary measures to improve cardiovascular prognosis.

References

García-Ríos A, Romero-Cabrera JL, Alcalá-Díaz JF, Quintana-Navarro GM, Martín-Piedra L, Arenas-de Larriva AP, Torres-Peña JD, Rodriguez-Cantalejo F, Kales SN, Ordovás JM, Pérez-Martínez P, Delgado-Lista J, López-Miranda J. Long sleep duration pattern is associated with increased cardiovascular recurrence: Effect of long-term Mediterranean diet from the CORDIOPREV study. J Intern Med. 2025 Sep;298(3):237-250. doi: 10.1111/joim.20119. Epub 2025 Jul 17. PMID: 40677148.