Sleep is essential for optimal health,1 yet more than one-third of US adults report insufficient sleep2 and 50 to 70 million people in the United States experience 1 or several sleep disorders.3 Both short and long sleep (<7 or >7 hours per night, respectively) have been associated with a greater risk of all-cause mortality and cardiovascular disease (CVD).4 Evidence links hypertension, coronary heart disease, and cerebrovascular disease to both ends of the sleep duration continuum (<5-6 hours or >8-9 hours).5,6 In addition to sleep duration, irregular sleep timing is associated with cardiovascular events.7 Irregular sleep timing (differing bedtimes and rise times for 1 week)7 represents the potential for circadian misalignment. Evidence has emerged demonstrating increased CVD risk among shift workers,8 as well as rise in cardiac events after daylight saving time,9 and in individuals who have longer sleep times on weekends compared with weekdays (called social jetlag).10,11

Populations at Risk

Some populations may be at a greater risk for sleep-related CVD risk. Many factors, such as the social determinants of health and lifestyle behaviors, influence sleep. Hale and colleagues12 observed that living in disadvantaged neighborhoods was associated with poor sleep quality, sleep disruptions, and insufficient sleep. Individuals with lower income and education levels experience a shorter sleep duration,13 of which occupational characteristics may play a role.14 Living arrangements and family structure have also been noted to affect sleep. Living alone and living with high levels of environmental noise contribute to sleep deficits.12,15 Adults with children report shorter sleep than those without children living in the home.12

Lifestyle behaviors, such as smoking, alcohol consumption, and physical inactivity, also influence an individual's sleep. Those who smoke report shorter sleep durations than nonsmokers and experience more insomnia symptoms than light smokers or nonsmokers.16 Alcohol consumption in nonalcoholics may promote sleep during the first half of the sleep period but disrupts sleep during the second half, leading to impaired sleep homeostasis.17 Binge drinking further disrupts sleep homeostasis.17

Women may be at a greater risk for cardiovascular effects of sleep restriction than men. Covassin and colleagues18 reported that 9 consecutive nights of sleep restriction resulted in elevated ambulatory blood pressure, impaired endothelial function, and stimulated sympathetic response among healthy adults. Of note, elevated blood pressure occurred only in women.

The COVID-19 pandemic has altered lifestyles resulting in sleep disturbances. Sleep problems continue to be common during this pandemic, affecting roughly 40% of the general and healthcare populations.19 A longitudinal study demonstrated that midsleep times (the midpoint between bedtime and wake time), which are indicative of the circadian system, were delayed, whereas midsleep variability and resting heart rate decreased.20 Healthcare workers are the most vulnerable population in the fight against COVID-19 and its variants because they are on the front lines. Approximately 40% of physicians and 35% of nurses reported sleep disturbances,21 and 36% to 41% of nurses experienced insomnia symptoms.22 The Society of Behavioral Sleep Medicine has issued objectives and recommendations for managing sleep problems during a pandemic. These guidelines include many resources for clinicians.23

Implications

Healthy sleep requires adequate duration, regularity of timing, daytime alertness, absence of sleep disorders, and good subjective quality.1 Sleep is a potentially modifiable behavior that is critical to the promotion of health and reduction of cardiovascular risk. The American Academy of Sleep Medicine issued a position statement in June 2021. The Academy recommended that healthcare providers routinely assess sleep habits, sleep symptoms, and sleep patterns and timing during patient encounters. They recommend that sleep health be "targeted by public health and workplace interventions to improve health-related outcomes, and behaviors that help people attain healthy sleep."24^(p2) The Academy also places a major emphasis on sleep health education in schools, in community and healthcare settings, in the workplace, and in public health policy arenas. The evidence-based recommendations issued by the Academy provide a "call to action" for nurses and nursing underscoring the importance of quality and quantity of sleep across the life course of individuals. Cardiovascular nurses are well positioned in clinical and community-based settings to implement the recommendations and advocate for the promotion of sleep health for patients, healthcare providers, and the public.

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