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Gregory Weiss, MD, provides insight into his perspective on the evolving recognition of the role of sleep health in cardiovascular disease prevention.
Cardiovascular disease (CVD) remains the leading killer of both men and women across the world. While marquee risk factors such as hypertension, diabetes, and obesity enjoy entire disciplines of medicine there exists a multitude of other factors that contribute to long-term CV risk.
Everyone knows how important sleep is. So much so that there are entire industries dedicated to facilitating our nightly quest for rest. Emerging evidence suggests that sleep patterns and disturbances may play a significant role in our long-term cardiovascular health as well.
Although there are quite a few sleep disorders, obstructive sleep apnea (OSA) is ubiquitous today with widespread obesity contributing to the disease burden significantly. It is estimated that nearly 1 billion people are affected by OSA worldwide.1 Sleep apnea is closely associated with the obesity hypoventilation syndrome marked by retained carbon dioxide and hypertension as well as cardiovascular disease.1 More recently OSA has been linked to coronary artery disease, stroke, and heart failure.1
In addition to sleep apnea, researchers have identified other sleep disturbances that contribute to CVD. A reduction in slow wave sleep (SWS) appears associated with OSA and is independently related to increased sympathetic activity which in turn increases the risk of cardiovascular and metabolic diseases.1 In essence, lack of slow wave sleep, or deep sleep, leads to cardiovascular stress and risk.
In addition to the quality of sleep, the duration of sleep appears to play a role in CV risk as well. Evidence suggests that those who sleep too little and those who sleep too much have higher rates of CVD.1 In particular, sleep durations less than 6 hours and greater than 10 were associated with increased rates of hypertension.1
Ultimately, the quality and duration of sleep are closely linked. Factors such as diet, stress, alcohol intake, and body composition are important in determining how much restful sleep each of us gets. Sleep apnea represents a cluster of symptoms and sequelae that affect several body systems. Through obstruction, usually due to excessive soft tissue in the mouth and neck, hypoventilation, increased CO2, and increased blood acid leads to changes in cardiovascular set points. Blood pressure and blood glucose levels rise leading to microvascular damage and cardiovascular disease.
The US Preventative Services Task Force thought the problem of OSA severe enough to put forth a set of recommendations this year.2 The task force recommends that positive airway pressure devices be employed when indicated for OSA.2 They further recommend screening in an effort to increase early detection and treatment.2 As with most conditions, especially ones that lead to cardiovascular disease, the earlier in the disease process treatment is started, the slower the progression to overt complications.
Sleep medicine is a discipline whose time has come. We are seeing clinicians from multiple disciplines choosing to enter this specialized field highlighting its newfound importance. In any case these reports shed important light on the link between healthy sleep and a healthy cardiovascular system. OSA, hypertension, daytime fatigue, and poor sleep go hand in hand. We now know that good sleep may just mean a healthier heart in the long run. As clinicians, especially primary care providers, we should screen our at-risk patients at every opportunity for sleep disturbances. Now, with an increasing number of clinicians choosing sleep medicine as a specialty, patients can get the help they need in finding that perfect nightly slumber, and just maybe a healthier cardiovascular system.