What is coronary heart disease?
Coronary heart disease (CHD) is a condition that is characterized by the blood vessels that supply blood to the heart muscle walls (coronary arteries) becoming obstructed by the accumulation of fatty deposits. If the blood supply to the heart is interrupted, oxygen and nutrients cannot travel through the blood to enrich the heart and provide energy. This means that the heart muscle will weaken over time. These events culminate in the medical emergency of a heart attack.
Is sleep important for heart health?
The average person sleeps for a third of their lifetime.1 Our bodies need sleep to recover and organise. Interestingly, the hours of sleep and the type of sleep you get can influence all aspects of your life, especially your health. Sleep is integral for the heart’s function, so much so that in a study of CHD patients, 39% of participants slept for too little (<6.5 hours), and 35% slept for too long (>8 hours).2 Sleep affects the heart directly by interfering with blood pressure and heart rate on the one hand and indirectly by influencing appetite, exercise and stress levels on the other.
Sleep helps regulate metabolism hormones
Metabolism and diet have an instrumental effect on heart health. Sleep affects the hormones that regulate appetite. During the recommended amount of sleep (8 hours at night), leptin (fullness hormone) levels increase whilst ghrelin (hunger hormone) levels decrease.3 Therefore, when an individual is in a sleep deficit state, these hormones are imbalanced, and they will experience increased amounts of hunger during the day, craving high-calorie foods. Consequently, chronic sleep loss will contribute to metabolic disorders like obesity. Obesity is a large risk factor for CHD as it correlates with high cholesterol in the blood (cholesterol contributes to the fatty deposits that block the coronary arteries) and increased blood pressure (your heart and vessels are put at risk of injury).4 It must be noted that sleep affects diet and metabolism. A poor diet will interrupt a good night’s sleep, creating a vicious risk factor cycle, so to avoid CHD, it is advised to make positive changes in lifestyle.
Lack of sleep increases the risk of coronary heart disease
Increased calcium build-up in coronary arteries
The plaque that blocks your arteries during CHD are calcified (or thickened), making the blockage robust, strengthening the blood flow barrier and stiffening the vessel walls. Normally, the vessels can withstand high pressure as it is muscular and flexible, however, during calcification of the plaque, rigid vessels are more susceptible to wall injury from high blood pressure. Fatty deposits within arteries form on top of areas of injury as a transient fix. Damage from vessel inflexibility increases the likelihood of further vessel blockages and restricted blood flow, which can trigger heart attacks. Studies showed that the calcification of arterial plaques increases with reduced sleep incidence.5 It was suggested that if a patient increased their sleep by merely one hour, the risk of plaque calcification decreased by 33%.6 Calcification is a multifactorial effect as blood pressure, inflammation, stress, and metabolism can all contribute to the process of calcification. Lack of sleep can directly alter all of these factors.
Increased blood pressure and heart rate
During normal sleep, your blood pressure goes down as your body rests and recovers.7 Reduced hours of proper sleep at night directly causes an increase in blood pressure throughout the day. High blood pressure contributes to CHD by adding stress to coronary artery walls. This will eventually cause vessel wall damage and eventually result in the formation of fatty blockage. Similarly, for heart health - the sympathetic nervous system activates the heart to work faster in times of sleep deprivation.8 The increased heart rate puts the heart and vessels under strain, contributing to heart fatigue as the muscle must work harder and causes an increase in blood pressure. A good sleep routine may ameliorate raised blood pressure and heart rate to avoid CHD risk.
What’s the best sleep position for heart health?
There is a lack of evidence regarding the best sleep position for heart health. Generally, sleeping on your back is recommended not just for good heart health, and puts less strain on the spine and internal organs. Despite this, getting a night of proper sleep is important for the overall health of an individual.
When to contact a doctor
CHD develops slowly over time, and the symptoms can vary according to the individual. Therefore, CHD often goes undetected until the incidence of a major cardiovascular event. Heart attack symptoms include sudden and sharp chest pain that often runs down the left arm, jaw, neck pain, dizziness, and light-headedness. Heart attacks are medical emergencies, so you must seek medical attention immediately. There are other factors like food habits (eating a heavy meal at night), stress etc., which can occasionally disrupt sleep patterns. However, if you face trouble sleeping on a regular basis and are anxious about how this will affect your health, contact your local GP for advice.
Summary
The right amount of good quality sleep has a significantly positive effect on your heart health. It is recommended for an adult to have 6- 8 hours each night. Along with a healthy diet, exercise, quitting smoking, and reducing stress, a good sleeping pattern is a step towards the prevention of CHD.
References
- Lin Y-L, Jhan Y-C, Lin H-W. A Good Partner in Sleeping: A Research on Customer Value Regarding Mattresses. EJBMR [Internet]. 2020 [cited 2022 Oct 27]; 5(6). Available from: https://ejbmr.org/index.php/ejbmr/article/view/667.
- Kim JH, Hayek SS, Ko Y-A, Liu C, Samman Tahhan A, Ali S, et al. Sleep Duration and Mortality in Patients With Coronary Artery Disease. The American Journal of Cardiology [Internet]. 2019 [cited 2022 Oct 27]; 123(6):874–81. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0002914918322136.
- Spiegel K, Tasali E, Penev P, Van Cauter E. Brief communication: Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Ann Intern Med. 2004; 141(11):846–50.
- Chan DC, Pang J, Watts GF. Dyslipidemia in Obesity. In: Ahima RS, editor. Metabolic Syndrome: A Comprehensive Textbook [Internet]. Cham: Springer International Publishing; 2016 [cited 2022 Oct 27]; p. 525–40. Available from: https://doi.org/10.1007/978-3-319-11251-0_30.
- Lutsey PL, McClelland RL, Duprez D, Shea S, Shahar E, Nagayoshi M, et al. Objectively measured sleep characteristics and prevalence of coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis Sleep study. Thorax [Internet]. 2015 [cited 2022 Oct 27]; 70(9):880–7. Available from: https://thorax.bmj.com/lookup/doi/10.1136/thoraxjnl-2015-206871.
- Short Sleep Duration and Incident Coronary Artery Calcification. JAMA [Internet]. 2008 [cited 2022 Oct 27]; 300(24):2859. Available from: http://jama.jamanetwork.com/article.aspx?doi=10.1001/jama.2008.867.
- Gottlieb DJ, Redline S, Nieto FJ, Baldwin CM, Newman AB, Resnick HE, et al. Association of Usual Sleep Duration With Hypertension: The Sleep Heart Health Study. Sleep [Internet]. 2006 [cited 2022 Oct 27]; 29(8):1009–14. Available from: https://academic.oup.com/sleep/article-lookup/doi/10.1093/sleep/29.8.1009
- Gangwisch JE, Heymsfield SB, Boden-Albala B, Buijs RM, Kreier F, Pickering TG, et al. Short sleep duration as a risk factor for hypertension: analyses of the first National Health and Nutrition Examination Survey. Hypertension. 2006; 47(5):833–9.
