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How Long You Sleep Affects Cardiovascular Disease Risk

2010-08-01 22:40

How long do you normally sleep each night? If your answer is less or more than seven hours, then you could be at an increased risk of cardiovascular disease, according to a new study from the West Virginia University School of Medicine in Morgantown.

Sleep Length and Cardiovascular Health Linked

According to the latest 2010 Sleep Foundation Poll, most people (white, black, Asians, Hispanics were polled) get less than seven hours sleep on average per night during the week, and show little increase on weekends. Blacks sleep less than other ethnic groups on both weekdays and weekends.

The West Virginia study analyzed data from 30,397 adults who had participated in the 2005 National Health Interview Survey. Subjects had revealed how many hours of sleep they averaged per 24-hour period. Among the participants, 2,146 cases of cardiovascular disease were diagnosed, including stroke, heart attack, coronary heart disease, or angina.

An evaluation of the sleep and health data revealed an elevated risk of cardiovascular disease among subjects who slept six and eight hours, but the association was strongest among those who slept five hours or less, who were younger than 60 years of age, and women. When the investigators accounted for people who had diabetes, depression, or hypertension, the risk remained more than two times higher for people who slept for five hours or less and nine hours or more when compared with people who slept seven hours.

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Overall, 8 percent of the participants reported sleeping five hours or less, while 9 percent said they slept nine or more hours per day. Although each person has his or her own personal sleep requirements, the American Academy of Sleep Medicine recommends that most adults get seven to eight hours of sleep per night.

Why does sleep have such an impact on cardiovascular disease? The authors suggest that sleep disturbances may impact endocrine and metabolic functions, such as glucose tolerance, or they may cause increased activity of the sympathetic nervous system, reduced insulin sensitivity, and elevated blood pressure, all of which can contribute to hardening of the arteries. People who sleep long may have an underlying breathing disorder. This study did not, however, identify possible causes for any association.

Anoop Shankar, MD, PhD, associate professor in the Department of Community Medicine at the University, noted that their findings “may have important clinical and public health implications, such as screening for changes in sleep duration by primary care physicians as a potential risk factor for cardiovascular disease, or initiating public health initiatives focusing on improving sleep quality and quantity.”

SOURCES:
American Academy of Sleep Medicine
Sleep Foundation
West Virginia University School of Medicine

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