Lifestyle Medicine and Sleep

“One particular area of interest in cardiovascular literature has been the issue of Sleep Disordered Breathing in cardiovascular disease.”

Sleep is essential for life itself and optimal health. Sleep plays a significant role in virtually every aspect of living including metabolism, brain function, systemic physiology, appetite regulation and the function of the cardiovascular system as well as the immune system and hormonal systems. Lifestyle factors play a very important role in maintaining healthy sleep. For all these reasons, it is highly appropriate that healthy, restorative sleep is one of the six pillars of lifestyle medicine.

As a cardiologist, I have been particularly interested in the area of sleep and its role in the normal functioning of the cardiovascular system. The American Heart Association (AHA) shares my level of interest and concern in this area. In fact, several years ago, the AHA listed a framework for lowering the risk of cardiovascular disease entitled “Life’s Simple 7.” Last year, the AHA modified this framework with an 8^th added factor and changed the mantra to “Life’s Optimal 8.” What do you think the 8^th criteria for cardiovascular health was? Normal, healthy sleep!

In this issue of the American Journal of Lifestyle Medicine, we are delighted to present 4 articles on sleep and health which comprise the core of the theme of this issue’s theme of “Sleep and Lifestyle Medicine.” These articles range from a study on sleep disorders and sleep health education in pregnant women, ¹ sleep quality during COVID-19 with a particular emphasis on quarantine, mental health and stress, ² sleep quality as a key component of improving mental and physical health in Japanese students ³ and the association between daily activities, stress and sleep among adults during the COVID-19 pandemic.

While the study designs and findings are somewhat different among the four studies, there is a strong unifying theme that sleep is a key health determination. This concept has been true for many years but as research has grown in this area it has become even more apparent. The linkage between sleep and health and issues related to lifestyle became of particular interest during the COVID-19 pandemic where significant disruptions in levels of physical activity, nutrition, and stress all impacted on sleep quality and duration. Clearly, there is also a bi-directional relationship since sleep quality also impacts on other lifestyle habits and practices such as level of physical activity, types of food consumed, stress levels, and meal timing.

Sleep disorders are extremely common in the United States. It has been estimated that over 70 million people in the United States have a chronic sleep disorder that adversely impacts on daily functioning and health and increases the risk of various chronic diseases including cardiovascular disease (CVD). The National Sleep Foundation in a 2014 survey reported that 35% of American adults rated their sleep quality as “poor” or “only fair.” Disrupted sleep at least one night per week was reported by 40% of respondents, while 53% of respondents had trouble staying asleep at least one night for the previous week and at least 23% of respondents had trouble staying asleep for five or more nights in a given week. Snoring was also common and reported by 40% of respondents. Of note, only 17% of respondents had been told by a physician that they had a sleep disorder which suggests that the diagnosis of sleep disorders remains suboptimal!

While many physicians focus on a particular kind of sleep disorder, usually obstructive sleep apnea (OSA), this is only one of over 100 different kinds of sleep disorders which have been identified. There are multiple short and long-term health consequences of sleep disruption. For example, it has been reported that short sleep disruption is associated with both anxiety and depression and exerts adverse influences on cognition and mood. Sleep disruption may also be associated with increased feelings of irritability and impatience. In one study of primary care physicians, disruptive sleep was associated with high burnout levels.

In addition, to the short-term health consequences of sleep disruption, there are multiple long-term consequences of sleep disruption impacting on many bodily systems particularly the cardiovascular system where sleep disruption is associated with increased levels of hypertension, dyslipidemia, weight related issues, metabolic syndrome, and type 2 diabetes. It is hypothesized that many of these negative impacts on the cardiovascular system may be the result of increased activity on the sympathetic nervous system which has been clearly associated with such issues as elevated blood pressure.

One particular area of interest in cardiovascular literature has been the issue of Sleep Disordered Breathing in cardiovascular disease. Sleep Disordered Breathing (SDB) is a subset of the general category of sleep disruption which is highly prevalent in individuals with cardiovascular disease and can also contribute to reduced quality of life. SDB can exacerbate ischemia, reduce systolic and diastolic function, cause cardiac structural and electrical remodeling, and increase the risk of cardiac arrhythmias and sudden death. Unfortunately, SDB often goes unrecognized both in general medical practice and specifically in cardiovascular practice.

As already indicated, SDB is a broader term than simply OSA although it should be noted that the most robust literature on cardiovascular risk has been developed in individuals with OSA. The reported prevalence of OSA varies considerably among various studies which may be related to using different criteria.

OSA may be as prevalent as 22% of the population. OSA can be found in 40%–80% of people with hypertension, heart failure, coronary heart disease or cerebrovascular disease. Patients with OSA typically report loud disruptive snoring and poor sleep quality as well as excessive daytime sleepiness which is a cardinal symptom. People with OSA often experience impaired quality of life. The diagnosis of OSA has been made based on symptoms such as snoring or breathing pauses or daytime sleepiness or fatigue. Sleep studies are typically utilized to diagnosis the degree of apnea or hypopnea in OSA.

The linkage between SDB and CVD in general appears to be related to sympathetic nervous system activity. Sympathetic activity increases during disordered breathing which may also augment an inflammatory response and hypercoagulability as well as exacerbating insulin resistance and lipolysis.

It should be emphasized that quality and duration of sleep changes as people grow older. As many as 50% of older individuals complain of sleep problems including “disturbed” or “light” sleep, frequent awakenings, early morning awakenings, and undesired daytime sleepiness. These changes that occur with aging make it all the more important for individuals practicing in the area of lifestyle medicine to inquire of patients of all ages, but particularly those over the age of 65 years, about their sleep patterns.

The most significant change in sleep in older individuals is repeated or frequent interruption of sleep and long periods of wakefulness. This is possibly a result of age-dependent decreases in sleep homeostasis processes. It should be emphasized that even careful screening of older individuals who do not complain of sleep disturbances may still experience these changes as described. For these reasons, issues related to other lifestyle practices and sleep are particularly important in consultations for people over the age of 65.

A variety of lifestyle factors impact on sleep. For example, individuals who are obese are significantly more susceptible to sleep disturbances than individuals who are in the healthy weight range. An inactive lifestyle is also a significant risk factor for sleep disturbances. Nutrition can also play a significant role in the quality of sleep. It is well known that certain foods and drinks make it easier or harder to get to sleep. This became a significant problem during the COVID-19 epidemic when individuals frequently had disruptions in their nutritional patterns and timing. Both mealtime and sleep are subject to exquisite and inter-related timing. Many individuals had altered eating patterns which disturbed their sleep because of lifestyle changes.

The Physical Activity Guidelines for Americans 2018 emphasized that regular physical activity is one of the best ways to promote healthy sleep. ⁴ In addition, in one of the articles published in the current issue of AJLM, further emphasis is made about the value of exercising outdoors which may bring additional stress relief. ⁵

Lifestyle physicians should also be prepared to help individuals create an optimum environment for healthy sleep. This has often been summarized under the rubric “sleep hygiene.” This involves such factors as:

• • Setting a consistent sleep schedule

• • Following a nightly routine

• • Cultivating healthy daily habits

• • Optimizing the bedroom

There is now abundant research demonstrating that healthy restorative sleep is a key consideration for virtually every aspect of daily living and health. It is essential for all lifestyle physicians to emphasize the importance of healthy sleep in each clinical encounter. Healthy sleep is one of the key pillars of lifestyle medicine and deservedly so!

James M. Rippe, MD

Editor in Chief, AJLM

Professor of Medicine

UMass Chan Medical School, Shrewsbury, MA