Irregular Sleep Patterns Double Risk of Cardiovascular Disease in Older Adults
Older adults with irregular sleep patterns—meaning they have no regular bedtime and wakeup schedule, or they get different amounts of sleep each night—are nearly twice as likely to develop cardiovascular disease as those with more regular sleep patterns, according to a new study funded in part by NHLBI.
The 5-year study suggests that an irregular sleep pattern may be a novel and independent risk factor for cardiovascular disease (CVD) and that maintaining regular sleep patterns could help prevent heart disease just as physical activity, a healthy diet and other lifestyle measures do, the researchers said.
Findings from the prospective study—the first believed to link sleep irregularity to the development of CVD—were published online Mar. 2 in the Journal of the American College of Cardiology.
“We hope that our study will help raise awareness about the potential importance of a regular sleep pattern in improving heart health. It is a new frontier in sleep medicine,” said lead study author Dr. Tianyi Huang, an epidemiologist with the Channing Division of Network Medicine at Brigham and Women’s Hospital in Boston.
“Research has linked irregular sleep schedules to a constellation of disease-causing abnormalities in body function, including changes in blood sugar and inflammation,” added Dr. Michael Twery, director of NHLBI’s National Center on Sleep Disorders Research. “This study is important because it is among the largest of its kind and it specifically associates these irregular sleep patterns with an increased risk for cardiovascular disease.”
Previous studies have linked insufficient amounts of sleep to a higher risk of obesity, diabetes and heart disease, which is why doctors emphasize the importance of getting 7 to 8 hours of sleep per night. Although researchers have suspected that high day-to-day variability in sleep duration and timing might also have negative effects on heart health, its effect remained unclear.
The association between irregular sleep and CVD appeared stronger among racial/ethnic minority populations, particularly African Americans, than among whites, the researchers said. This finding is consistent with recent studies that show racial minorities tend to have a higher risk of sleep disorders than whites. Although past studies suggest that women are more likely than men to be affected by unhealthy sleep, the current study did not find significant gender differences.
The researchers said they are unclear about the exact biological mechanisms behind the sleep irregularity and CVD link, but they suspect that multiple factors, including harmful disturbances in the body’s circadian rhythm—the 24-hour internal body clock that controls the sleep-wake cycle—may be in play.