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Healthy sleep habits are essential for optimal health and wellness; yet approximately one third of US adults get less than the recommended amount of sleep.¹ Sleep deprivation alters multiple aspects of both behavior and physiology, and observational studies have associated chronic sleep deprivation with increased risk of cardiovascular events and all-cause mortality.² Poor sleep quality, which may be characterized as short sleep (less than seven hours per 24-hour period), fragmented sleep, or a sleep disorder such as insomnia or sleep apnea has also been linked to cardiovascular disease (CVD) incidence.^3-6 What lifestyle therapies for better sleep may help to prevent cardiovascular damage and improve health?

Sleep Durations & Disorders: Cardiovascular and Metabolic Consequences

Recent studies have focused on the relationship between both chronically short and long sleep durations and cardiometabolic profiles in adults.⁷ For example, a 2021 meta-analysis of 13 cohort studies (n=300,202 total adult participants) found that both short (less than six hours) and long sleep (greater than eight hours) significantly increased the risk of metabolic syndrome by 15% and 19%, of obesity by 14% and 15%, and of high blood pressure by 16% and 13%, respectively.⁸ Another meta-analysis from 2021 (17 cohort studies; n=737,002 adult participants) found that short sleep duration (less than six hours) was associated with 4.73% type 2 diabetes incidence, long sleep duration (greater than nine hours) was associated with 4.99% incidence, while normal sleep duration (between six and nine hours) had a 4.39% incidence of type 2 diabetes.⁹ Other recent observational studies have also suggested that both short and long sleep durations are associated with a higher risk of stroke incidence and stroke mortality⁵ and may contribute to subclinical CVD.¹⁰

Insomnia

Insomnia is a common sleep disorder, with an estimated 14.5% of US adults reporting difficulties falling asleep and 17.8% of US adults reporting trouble staying asleep.¹¹ Insomnia has been linked to a higher risk of hypertension, increased adiposity, and type 2 diabetes in some studies.^12,13 A recent prospective cohort study (n=487,200 adults; ages 30-79 years) also found that individual and coexisting insomnia symptoms were independent risk factors for CVD incidence, particularly among young adults or adults without hypertension at baseline.¹⁴ In this cohort, researchers tracked participants for nearly a decade, and those who reported trouble focusing during the day were 13% more likely to develop heart attack, stroke, and comparable diseases than those who did not have problems focusing.¹⁴ Participants who found it difficult to fall asleep or stay asleep had a 9% higher chance of developing CVD, while those who woke up too early were 7% more likely to experience a stroke, heart attack, or similar incident.¹⁴ The results suggest that identifying insomnia, particularly in young people, may reduce CVD risk later on in life.

A 2023 meta-analysis of nine observational studies (n=1,184,256 total participants) also investigated the relationship between insomnia and CVD, focusing on incidence of myocardial infarction.⁴ Results indicated a significant association between the two. Compared to non-insomniacs, those experiencing insomnia had a 69% higher risk of myocardial infarction incidence.⁴ The highest association was noted when sleep duration was equal to or less than five hours.

Obstructive Sleep Apnea

Sleep-disordered breathing like obstructive sleep apnea (OSA) leads to fragmented night sleeping and daytime sleepiness, and evidence suggests that OSA may be associated with the development of a range of cardiovascular diseases.^6,15 Not only do adults with OSA have an increased risk of developing comorbid CVD, many may also experience worse outcomes.¹⁵ Interestingly, OSA is highly prevalent, especially among those with cardiovascular dysfunction; it has been estimated to affect 40-60% of US patients with CVD.¹⁵ While multiple CVD processes are associated with OSA, the relationship with hypertension has been most clearly established.^15,16 A 2021 meta-analysis also indicated that patients with OSA may have more cardiovascular damage, measured by higher rates of coronary atherosclerosis development.¹⁷ OSA also has links to prediabetes and diabetes. A 2022 meta-analysis of 25 observational studies (n=154,948 total patients with OSA) found that patients with OSA had increased odds of impaired fasting glucose, impaired glucose tolerance and regulation, and diabetes development.¹⁸

Steps to Improve Sleep

Many study outcomes, as mentioned above, highlight the importance of healthy sleep habits for cardiovascular and metabolic health, and a nutritious diet,¹⁹ physical exercise,²⁰ cognitive interventions,²¹ and relaxation techniques²¹ may all help to induce sleep or help the body heal from insufficient sleep. Specific to nutrition, deficiencies in vitamin B1, folate, phosphorus, magnesium, iron, zinc, and selenium have been associated with shorter sleep duration; lack of alpha-carotene, selenium, and calcium with difficulty falling asleep; low intake of vitamin D and lycopene with problems with sleep maintenance; and low intake of calcium and vitamin C with non-restorative sleep.²² Protein and carbohydrate deficiencies have also been associated with shorter sleep duration.²²

Increasing evidence also demonstrates a reverse relationship, with disrupted sleep patterns prompting unhealthy eating behaviors^23,24 that may contribute to cardiometabolic risk. Short sleep duration, poor sleep quality, and later bedtimes may all promote increased food intake, poor diet quality, and excess body weight.²⁴ In addition, lack of sleep has been suggested to increase the preference for energy-rich foods.²⁴

Research results suggest that sedentary behavior²⁵ and ultra-processed food consumption²⁶ may be associated with anxiety-induced sleep disturbance. Studies point to the need for mental health screening for all, as well as the integration of lifestyle interventions to modulate sleep.^25-27 When anxiety and depression start to negatively affect sleep patterns, this may have a detrimental effect on heart health. Evidence suggests that persistent anxiety and depression could be tied to negative long-term effects on cardiovascular health and may play a major role in triggering critical cardiac events like stroke, myocardial infarction, and congestive heart failure.^28,29

Conclusion

Taken together, the studies outlined in this report illustrate the importance of healthy sleep habits for heart and overall health. A close working relationship between clinician and patient can help identify sleep troubles early on so that they may be targeted with behavioral and lifestyle therapies to prevent or reverse cardiovascular damage. Learn more about tools and strategies to help patients achieve sustainable lifestyle change and improve their well-being through IFM’s new course Lifestyle: The Foundations of Functional Medicine.

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References

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