People who get at least 8 hours of sleep each night are more likely to have good heart health than those who get less sleep, a new study finds.
In the study, researchers compared groups of people who slept for different average lengths of time, looking at how well each group met the seven criteria from the American Heart Association for "ideal" heart health.
The researchers found that people who slept 8 or more hours a night were 2.7 times more likely to meet six or seven of the ideal heart-health criteria, compared with people who got less than 6 hours of sleep a night.
Although previous studies have linked people's sleep duration to negative outcomes, such as their risk of heart disease, few studies have looked at sleep duration and good outcomes, such as ideal heart health, said the researchers. They presented their study Tuesday (Nov. 10) here at the American Heart Association Scientific Sessions.
In the study, the researchers looked at data on 9,700 people who were all employees at a health organization called Baptist Health South Florida. The employees filled out questionnaires that included questions about their lifestyle habits such as their diet, smoking, physical activity levels, and sleep duration and quality. People in the study were divided into three groups based on how long they slept: less than 6 hours a night, 6 to 7.9 hours a night and 8 or more hours a night.
The researchers looked at how many "ideal" targets of heart health each participant met. The targets include having blood pressure under 120/80 mm Hg, a body mass index under 25, a blood glucose level under 140 mg/dL, a total cholesterol level under 200 milligrams per deciliter (mg/dL), getting at least 150 minutes of physical activity a week, earning a score of 8 out of 10 on the AHA's scoring of an ideal diet and not smoking (a breath test was used to identify smokers).
The researchers also collected data on the employees' body mass index, blood pressure, and blood glucose and cholesterol levels.
The researchers found that people who slept 8 hours were more 1.6 times more likely to eat an ideal diet, 1.7 times more likely to have an ideal BMI, 1.3 times more likely to have ideal blood pressure and 2.4 times more likely to get enough physical activity, compared with those who slept less than 6 hours.
The researchers noted that the majority of people in the study who got less than 6 hours of sleep a night were more likely to be female, and to not have a college degree.
The results from the study do not prove cause and effect, meaning getting less sleep does not necessarily cause someone to meet fewer of the heart health metrics. However, the researchers concluded that getting more sleep is associated with ideal heart health and that the "findings underscore the importance of promoting sleep health in a working population."
Still, the researchers noted that more studies are needed to confirm the results. This study has not been published in a peer-reviewed journal.