Getting enough sleep is good for you. Old news, right? A new study from the American Academy of Sleep Medicine expands on this generic health advice, finding that excess heart age is the lowest in adults who sleep seven hours a night: no more, no less.
Sleep is important for a variety of reasons. It promotes learning and memory function in the brain. Sleep also boosts attention span, decision making, and creating thinking. Additionally, sleep is vital for repairing heart and blood vessels. From past studies, scientists know that sleep deficiency is linked to increased risk of heart disease, kidney disease, high blood pressure, diabetes, and stroke.
According to the American Sleep Association, between 50 and 70 million adults in the United States have a sleeping disorder, like insomnia, sleep apnea, or narcolepsy. Almost half of American report snoring, and insomnia is recorded as the most common specific sleep disorder.
In their new study, scientists analyzed data from 12,775 adults between the ages of 30 and 74 who completed a survey on health and nutrition. Each respondent self-reported sleep habits, which were separated into five categories: five hours or less, six hours, seven hours, eight hours, and nine hours or more per night.
Researchers determined each respondent’s heart age using the Framingham heart age algorithm. This tool, also called the Framingham heart age calculator, factors in sex, systolic blood pressure, hypertension status, smoking habits, diabetes status, and BMI (body mass index) to produce the individual’s “heart/vascular age,” personal risk of disease, the normal risk, and the optimal risk. The test is intended for use by people between ages 30 and 74 with no history of heart disease.
Researchers identified associations between this measurement and sleeping patterns in the 12,775 respondents. They found that sleeping times less than or greater than seven hours were associated with increased excess heart age. However, excess heart age was found to be the greatest for people sleeping less than seven hours.
"These results are important because they demonstrate a quantitative method for the inclusion of sleep duration in the establishment and communication of cardiovascular risk for individuals,” explained primary researcher Julia Durmer. “This could have utility in the clinical care of patients with cardiovascular risk, and for public health researchers interested in adding a sleep metric to future studies.”
The research abstract was recently published online in the journal Sleep.