A Few Words About Sleep and the Heart
Yet, nowadays, more and more people sacrifice their rest hours on the altar of obligations and intense daily life.
Disturbed sleep, either due to reduced duration or poor quality, not only affects our energy levels and mood, but also appears to have serious impacts on our cardiovascular health.
What is the relationship between sleep and heart health? How do the quality and quantity of sleep affect the risk of developing cardiovascular diseases? In this article, we will see what research shows and how we can protect our heart starting… from our bed.
What Are Sleep Disorders?
Sleep disorders are conditions that negatively affect the quality and duration of sleep, resulting in the body not resting adequately.
They are particularly common, with recent research findings showing that approximately 1 in 3 adults experience sleep disorders, such as difficulty falling asleep, frequent awakenings, or daytime sleepiness.
The truth is that most of us will experience difficulties with our sleep at some point in our lives, and this usually happens after a temporary period of stress or changes in our daily routine. However, in most cases, sleep patterns gradually return when daily life returns to its normal rhythms.
Of course, if sleep difficulties persist for an extended period, there is a possibility they may develop into a more serious and chronic disorder, affecting our quality of life.
There are about 80 different types of sleep disorders.
The main ones are:
- Insomnia. Insomnia is the most common sleep disorder and is characterized by difficulty falling asleep (trouble getting to sleep), maintaining sleep (frequent awakenings during the night), and/or early awakening without being able to fall back asleep.
- Sleep Apnea. Sleep apnea is characterized by pauses in breathing during sleep. There are two types of sleep apnea: obstructive, where airflow is interrupted due to upper airway obstruction, and central, where the interruption is attributed to a decrease in respiratory effort.
- Parasomnias. Parasomnias are a category of disorders that cause abnormal movements and behaviors during sleep. They include sleepwalking, sleep talking, nightmares, teeth grinding, or jaw clenching.
- Narcolepsy. It is a neurological sleep disorder characterized by excessive sleepiness and sudden episodes of sleep during the day, even at inappropriate times — such as at work, while driving, or during conversation.
- Restless Legs Syndrome. Restless legs syndrome causes an intense, often uncontrollable need to move the legs, usually in the evening hours or when lying down.
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Quality sleep is not just about rest and relaxation – it is vital for our cardiovascular health. When sleep is inadequate, it can burden the heart and blood vessels through multiple mechanisms such as:[1]
Increased Blood Pressure (Hypertension)
During quality and sufficient sleep, blood pressure naturally decreases – a condition that allows the heart and blood vessels to ‘relax’ and recharge.
However, when sleep is inadequate or interrupted, this normal process does not occur or occurs partially. The result is that the cardiovascular system remains on alert, as it does during the day.
This can gradually lead to increased levels of blood pressure, namely hypertension, which burdens the heart and blood vessels and increases the risk of cardiovascular diseases, such as stroke, myocardial infarction, and heart failure.
Increased Levels of Inflammation
Insufficient sleep is associated with increased levels of inflammatory markers, such as interleukin-6 and C-reactive protein (CRP).
Chronic inflammation can lead to injury of the endothelium, the thin layer of cells that lines the interior of blood vessels, triggering the process of atherosclerosis. Atherosclerosis is a chronic progressive disease of the arteries that can lead to serious cardiovascular diseases (such as heart attack and stroke).
Although the mechanism by which sleep deprivation leads to inflammation is not known, one theory focuses on blood vessels.
During sleep, blood pressure drops and blood vessels relax. When sleep is limited, blood pressure does not decrease as much or for as long as it should, which likely stimulates cells in the walls of blood vessels to activate the inflammation process.
Moreover, sleep deprivation interferes with the normal function of the brain’s ‘cleaning system’.
During deep sleep, the so-called glymphatic system is activated – a “cleaning system” of the brain. Through the glymphatic system, cerebrospinal fluid circulates in the brain, removing toxins and waste products, including the beta-amyloid protein associated with brain cell damage and Alzheimer’s disease.
When sleep is insufficient, this “cleaning” mechanism underperforms, resulting in the accumulation of beta-amyloid and increased inflammation in the brain.
Cardiac Arrhythmias
In sleep disorders such as sleep apnea, repeated breathing interruptions during the night can significantly affect heart function.
Each apnea episode causes a temporary drop in blood oxygen levels (hypoxia) and simultaneously leads to sudden fluctuations in heart rate.
These cardiac arrhythmias can strain the heart, lead to cardiac dysfunction, and increase the risk of heart failure.
Increased Body Weight
There are numerous studies in the literature reporting that disrupted sleep is associated with an increased risk of obesity.
Recent findings suggest that lack of sleep can affect body weight and fat distribution, promoting fat accumulation in the abdominal area.
This is particularly important as abdominal fat, especially visceral fat, has been linked to an increased risk of chronic health diseases such as cardiovascular diseases, among others.
What is the relationship between disrupted sleep and the onset of cardiovascular diseases?
In recent years, the relationship between disrupted sleep and cardiovascular diseases has been extensively studied, with scientific evidence being quite strong.
Many epidemiological studies have shown that disrupted sleep is associated with an increased risk for:[2]
- Coronary Heart Disease
- Myocardial Infarction
- Stroke
- Heart Failure
- Cardiac Arrhythmias
A meta-analysis that included 22 prospective studies and over 517,000 participants concluded that both short (≤6 hours) and long (>8 hours) sleep duration are associated with an increased risk of coronary heart disease.[3]
Specifically, for every one hour reduction in sleep duration below 7 hours, the risk for coronary heart disease increases by 11%. Also, for every one hour increase in sleep duration above 7 hours, the risk increases by 7%.
This meta-analysis showed that the relationship between sleep and coronary heart disease has a U-shape, with the lowest risk observed at 7-8 hours of sleep per day. This indicates that both lack of sleep and excessive sleep are risk factors for cardiovascular diseases
In fact, in 2022, the American Heart Association officially recognized sleep as a key factor for heart health. Until then, there were seven key factors considered essential for a healthy heart — the so-called Life’s Simple 7 list. Now, with the addition of sleep, this list has been renamed to Life’s Essential 8.[4]
This list includes:
- Healthy diet. Adopt a healthy and balanced diet that emphasizes fruits, vegetables, legumes, whole grains, and sources of “good” fats, while limiting red and processed meat, foods and drinks with added sugars and salt, and alcoholic beverages.
- Adequate Physical Activity. Aim for at least 150 minutes of moderate-intensity exercise (such as brisk walking) or 75 minutes of vigorous exercise (such as running) per week.
- Maintaining a healthy body weight. Maintain a normal Body Mass Index (BMI) and body fat percentage.
- Avoiding Smoking. Avoiding smoking and nicotine products is essential, as they dramatically increase cardiovascular risk.
- Maintaining normal cholesterol levels. Aim for low levels of “bad” cholesterol and adequate levels of “good” cholesterol, as they help prevent the formation of atherosclerotic plaque and reduce the risk of coronary heart disease and other cardiovascular diseases.
- Maintaining Good Glycemic Control. Aim for normal blood glucose levels. Regulating blood glucose levels helps prevent type 2 diabetes and reduces the risk of cardiovascular diseases, which are common complications of diabetes.
- Maintaining blood pressure at normal levels. Aim for normal blood pressure levels (<120/80 mmHg) to protect blood vessels and the heart from long-term damage.
- Adequate Sleep. Aim for 7-9 hours of quality sleep daily.
Conclusion
Sleep is not a luxury — it is a fundamental need for our overall well-being and heart health. The scientific evidence is clear: the quality and quantity of sleep significantly affect our heart, just as much as diet, exercise, and smoking cessation.
If we want to protect our heart, reduce the risk of chronic diseases, and improve our overall quality of life, we need to give sleep the importance it deserves.
Turn off the light, move away from screens, and invest in sleep that not only rests the body — but also fortifies your health.
Don’t forget: heart care starts in bed.
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Book AppointmentBibliography
[1]Jaspan V, Greenberg C, Parihar S, Park C, Somers V, Shapiro M, Lavie C et all. The Role of Sleep in Cardiovascular Disease. Curr Atheroscler Rep. 2024, 26(7):249-262. doi: 10.1007/s11883-024-01207-5.
[2] Wang S, Li Z, Wang X, Guo S, Sun Y, Li G, Zhao G. Associations between sleep duration and cardiovascular diseases: A meta-review and meta-analysis of observational and Mendelian randomization studies.
[3] Wang D, Li W, Cui X, Meng Y, Zhou M, Xiao L, et al. Sleep duration and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies. Int J Cardiol. (2016) 219:231–9. 10.1016/j.ijcard.2016.06.027.
[4] American Heart Association. Life’s Essential 8Available at: https://www.heart.org/en/healthy-living/healthy-lifestyle/lifes-essential-8. (Accessed at April 2025).
