Data from a recent study are scheduled to be presented Sunday, Nov. 14 at the American Heart Association Scientific Sessions in Chicago by Alanna Morris, MD, a cardiology fellow at Emory University School of Medicine, shows that people who do not get enough sleep have higher inflammation levels there by being in higher risk for stroke or heart attack.
The results come from surveying 525 middle-aged people participating in the Morehouse-Emory Partnership to Eliminate Cardiovascular Health Disparities (META-Health) study on their sleep quality and sleep duration. The META-Health study’s co-directors are Arshed Quyyumi, MD, professor of medicine at Emory University School of Medicine and director of Emory’s Cardiovascular Research Center, and Gary Gibbons, MD, director of the Cardiovascular Research Institute at Morehouse School of Medicine. Donald Bliwise, MD, director of the Emory University Sleep Program, contributed additional guidance.
Acute sleep deprivation leads to an increased production of inflammatory hormones and changes in blood vessel function, but more research is needed on the physiological effects of chronic lack of sleep, Morris says.
In the META-Health study, the researchers assessed sleep quality using the Pittsburgh Sleep Quality Index survey, where a score over six (based on the median sleep score of the study population) is considered poor. They also analyzed their data based on hours of sleep.
Individuals who reported six or fewer hours of sleep had higher levels of three inflammatory markers: fibrinogen, IL-6 and C-reactive protein. In particular, average C-reactive protein levels were about 25 percent higher (2 milligrams per liter compared to 1.6) in people who reported fewer than six hours of sleep, compared to those reporting between six and nine hours.
C-reactive protein is used extensively as a marker of inflammation and heart disease risk. People whose C-reactive protein levels are in the upper third of the population (above 3 milligrams per liter) have roughly double the risk of a heart attack, compared with people with lower C-reactive protein levels, according to the American Heart Association and Centers for Disease Control and Prevention.
“For people who got little sleep, the C-reactive protein levels were increased, but still in the range of what health authorities would consider low to intermediate risk,” she says. “However, our study population represents a community-based population [as opposed to patients in the hospital or with known cardiovascular disease], so they have overall lower risk and lower C-reactive protein levels than many of the high risk populations in other studies.”
Previous research has shown that people who sleep between seven and eight hours per night live longest, and that especially short or especially long sleep durations bring higher mortality. Researchers find that short and long sleep durations are often seen together with high blood pressure, obesity, diabetes and psychological stress – all risk factors for heart disease and stroke.