American Heart Association

04/14/2025 | Press release | Distributed by Public on 04/14/2025 03:22

Sleep matters: duration, timing, quality and more may affect cardiovascular disease risk

Sleep matters: duration, timing, quality and more may affect cardiovascular disease risk

More research is needed to understand how different components of sleep affect cardiometabolic health and the interventions that may optimize sleep health, according to a new American Heart Association scientific statement

Statement Highlights:

  • While the strongest evidence exists that getting sufficient sleep (duration of sleep) is important for overall health , other components of sleep health, such as consistent bedtime, uninterrupted sleep, daytime functioning and self-reported sleep satisfaction, also contribute to cardiometabolic health and related risk factors, including heart disease, stroke, high blood pressure, high cholesterol, inflammation, glucose intolerance, obesity and obstructive sleep apnea.
  • Differences in sleep health may contribute to increased risk factors and worse health outcomes, particularly for people in under-resourced communities and individuals affected by adverse social drivers of health, such as lower socioeconomic status, housing instability and/or discrimination.
  • Health care professionals are encouraged to discuss sleep health with patients, and targeted research is needed to identify effective interventions to improve sleep health and reduce the risk of cardiometabolic health conditions.

Embargoed until 4:00 a.m. CT/5:00 a.m. ET Monday, April 14, 2025

DALLAS, April 14, 2025 - Healthy sleep includes multiple components, such as number of hours of sleep per night, how long it takes to fall asleep, daytime functioning and self-reported sleep satisfaction, and addressing these different dimensions of sleep may help to reduce cardiometabolic health and related risk factors, according to a new American Heart Association scientific statement published today in Circulation: Cardiovascular Quality and Outcomes.

The new scientific statement, "Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health," describes multiple components of sleep health, such as sleep duration, continuity, timing, satisfaction, regularity and daytime functioning. The scientific statement also reviews the latest evidence on what is known about the relationship between sleep and various cardiometabolic health factors, including body fat, blood sugar, cholesterol and blood pressure, and how healthy sleep positively impacts physical health and mental well-being.

"Most adults need 7 to 9 hours of sleep each night, and suboptimal sleep raises the risk for cardiovascular disease, along with risk of cognitive decline, depression, obesity, as well as high blood pressure, blood sugar and cholesterol levels," said Chair of the scientific statement writing group Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, an associate professor of nutritional medicine in the department of medicine and director of the Center of Excellence for Sleep & Circadian Research, both at Columbia University Irving Medical Center in New York City. "However, there is increasing evidence that sleep health is about more than the number of hours you sleep each night."

Sleep and cardiometabolic health

According to the scientific statement, no single facet of sleep health fully captures people's sleep experiences and how their individual body responds. The less-discussed and less-studied components of sleep health are relevant to the sleep experience and contribute to overall physical and mental health and well-being. Sleep components include:

  • Sleep duration is the number of hours per night (or per 24-hour period) an individual sleeps. It can be estimated via a person's self-reported number of hours spent sleeping using questionnaires and diaries, or assessed objectively via actigraphy (wearing a device that tracks movement) or polysomnography (using sensors to monitor brain activity, breathing, heart rate, blood oxygen and eye movements that gauge sleep). The latest evidence from multiple studies indicates that sleeping less than 7 hours a night increases the risk of atrial fibrillation, cardiometabolic syndrome (a group of conditions that increases the likelihood of Type 2 diabetes, heart disease or stroke) and blood pressure that doesn't decrease as much during sleep (blood pressure should be lower at night/when sleeping vs. during the day/when awake and active). Too much sleep or sleeping more than 9 hours per night is also associated with an increased risk of cardiometabolic syndrome, stiff arteries, stroke or death from heart disease or stroke.
  • Sleep continuity is the proportion of time spent sleeping. It is calculated based on factors that represent sleep difficulties, such as the time it takes to fall asleep, how many times a person wakes up during the night, the amount of time spent awake during the night, (after falling asleep) unplanned early awakening and obstructive sleep apnea. Disturbance in sleep continuity has been associated with a higher risk of atrial fibrillation, heart attack, high blood pressure or more insulin resistance.
  • Sleep timing refers to the time a person typically goes to sleep during a 24-hour period. Studies evaluating sleep timing examine how cardiometabolic risk changes with a person's usual bedtime and whether they are sleeping in the night versus daytime hours. High-quality research on sleep timing is limited, however, data indicate that suboptimal timing of sleep is likely to be associated with increased cardiovascular disease risk factors. A reported bedtime of midnight or later, compared to earlier than midnight, has been associated with higher risk of overweight or obesity, insulin resistance and elevated blood pressure.
  • Sleep satisfaction is a person's own perception of their sleep experience. A combined analysis of recent research indicates that lower satisfaction with sleep is associated with higher blood pressure, stiff and less flexible arteries, coronary heart disease and nighttime blood pressure that doesn't decline.
  • Sleep regularity is the stability of a person's sleep duration/timing across days (for example, if the number of hours spent asleep changes between workdays and weekends, this is called "social jetlag"). Social jetlag has been associated with a 20% higher risk of having overweight or obesity, and day-to-day variability in sleep timing has been associated with a higher risk of cardiovascular disease, high blood pressure, inflammation, obesity and blood pressure that doesn't decrease during the night. In large-scale studies, greater consistency in sleep-wake timing has been associated with a 22%-57% lower risk of cardiovascular death. In a large UK Biobank study, irregular sleep timing was linked to a higher risk of Type 2 diabetes even in people who had sufficient sleep, with the highest risk among those who had too little sleep and very irregular sleep patterns.
  • Sleep-related daytime functioning is a person's ability to remain alert and awake during the day (including how sleepy or tired they feel). It can be estimated by participants' self-reported information about how likely they are to doze off in certain situations (such as watching TV or riding in a car) or by evaluating a person's cognitive alertness (such as testing reaction time to visual or auditory cues). Excessive daytime sleepiness is associated with cardiovascular disease, coronary heart disease, stroke and death from both cardiovascular disease and all causes. Certain cardiovascular risks, including obesity, Type 2 diabetes, depression, smoking and obstructive sleep apnea, were associated with a higher risk of daytime sleepiness, while weight loss appeared to reduce excessive sleepiness during the day.
  • Sleep architecture refers to sleep stages that the body typically cycles through while asleep, assessed using electroencephalography (EEG) to measure electrical activity in the brain. Sleep is divided into two categories: non-rapid eye movement (NREM), which includes stages of light sleep and deep sleep; and rapid eye movement (REM), the deepest stage of sleep. Disruptions in sleep continuity can interfere with sleep stages differently. One analysis of combined studies noted that interrupting NREM, also known as slow-wave sleep, led to higher levels of insulin resistance compared to non-interrupted sleep.

Differences in sleep health

The statement also addresses differences in sleep health for people affected by adverse social drivers of health. A recent review of more than 300 studies found consistent associations between lower socioeconomic status and suboptimal sleep health. Social and environmental factors, including home and neighborhood characteristics such as light, air and noise pollution and safety, also contribute to differences in one or more components of sleep health.

Compared with non-Hispanic white people, individuals in historically underrepresented racial and ethnic groups sleep less and are more likely to experience worse sleep continuity, less satisfaction with sleep, later bedtimes, more irregular sleep, higher daytime sleepiness and a higher occurrence of sleep disorders . These differences are observed across the life span and persist over time, with Black adults having the worst sleep health among all people.

"It's important to know that every individual has different sleep experiences, and these differences may contribute to other health inequities," said St-Onge. "Including different components of sleep in discussions with patients provides essential information that can help health care professionals improve care."

Asking questions such as "How long does it typically take you to fall asleep each night?," "How many times do you wake up during the night?" and "How often do you feel exhausted during the day?" can give patients the opportunity to share concerns about their sleep experience and quality of sleep. Documenting sleep details in the patient's medical records will help the patient's health care team to be informed about the patient's sleep health and may prompt more in-depth evaluation or screening. This information is also helpful when considering how a patient's health conditions and prescribed medication regimen may interfere with sleep health and need to be adjusted or changed.

"Some changes in sleep across the life course are natural, however, individuals should not accept poor or worsening sleep as a 'fact of life' or unavoidable consequence of the aging process. If they note new difficulties falling or staying asleep, or excessive daytime sleepiness, they should discuss this with their doctor for further evaluation and potential treatment," said St-Onge.

More research needed to optimize sleep health

Awareness of the importance of sleep is growing, however, more research about the various dimensions of sleep health is needed so that clinicians can support patients with ways to promote healthy sleep and improve health. While there are numerous smartwatches and other personal devices available to track the amount of time spent asleep per night, advances in ways to assess other sleep dimensions are needed. Using data from both self-reported and objective measures can help ensure sleep health guidance is grounded in reliable and comprehensive information.

Sleep is one of the health metrics noted in Life's Essential 8, the American Heart Association's measures for optimal cardiovascular health. When incorporating sleep into the Life's Essential 8 score, the only measure for sleep is its duration (number of hours per night) because there isn't enough validated research yet confirming how to assess other sleep components.

According to some research studies, poor sleep health (such as short sleep duration and irregular sleep schedules) contributes to adverse cardiovascular outcomes. There is a need for evidence from clinical trials confirming that improving sleep health leads to better cardiometabolic health. This data could be useful in developing effective interventions to help people improve various components of their sleep, which, in turn, supports better cardiometabolic health.

Research studies on multidimensional sleep health would ideally include collaborative efforts across medical specialties, including sleep medicine, cardiology, endocrinology, gastroenterology, nephrology, pulmonology and neurology. In addition, individuals from under-represented racial and ethnic groups should be included in studies to capture the various components of sleep health in diverse populations and communities. Broader understanding and validated research about the impact of sleep on physical health and mental well-being are key to advancing cardiovascular health for all.

This scientific statement was prepared by the volunteer writing group on behalf of the American Heart Association's Council on Lifestyle and Cardiometabolic Health; the Council on Cardiovascular and Stroke Nursing; the Council on Clinical Cardiology; and the Council on Quality of Care and Outcomes Research. American Heart Association scientific statements promote greater awareness about cardiovascular diseases and stroke issues and help facilitate informed health care decisions. Scientific statements outline what is currently known about a topic and what areas need additional research. While scientific statements inform the development of guidelines, they do not make treatment recommendations. American Heart Association guidelines provide the Association's official clinical practice recommendations.

Additional members of the statement writing group and co-authors are Vice-Chair Michael A. Grandner, Ph.D., M.T.R, M.S., FAHA; Brooke Aggarwal, Ed.D., M.S., FAHA; Julio Fernandez-Mendoza, Ph.D.; Dayna Johnson, Ph.D., M.P.H., M.S.W., M.S.; Christopher E. Kline, Ph.D., M.S.; Kristen L. Knutson, Ph.D., FAHA; and Nancy Redeker, Ph.D., R.N., M.S.N., FAHA. Authors' disclosures are listed in the manuscript.

The Association receives more than 85% of its revenue from sources other than corporations. These sources include contributions from individuals, foundations and estates, as well as investment earnings and revenue from the sale of our educational materials. Corporations (including pharmaceutical, device manufacturers and other companies) also make donations to the Association. The Association has strict policies to prevent any donations from influencing its science content. Overall financial information is available here.

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About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. Dedicated to ensuring equitable health in all communities, the organization has been a leading source of health information for more than one hundred years. Supported by more than 35 million volunteers globally, we fund groundbreaking research, advocate for the public's health, and provide critical resources to save and improve lives affected by cardiovascular disease and stroke. By driving breakthroughs and implementing proven solutions in science, policy, and care, we work tirelessly to advance health and transform lives every day. Connect with us on heart.org, Facebook, X or by calling 1-800-AHA-USA1.

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