By Erin White
CHICAGO — White people seem to sleep longer at night, have a better quality of sleep and experience less daytime sleepiness than people identified as black, Hispanic or Asian, according to a new study from Northwestern Medicine.
“We found that black adults have the worst quality of sleep, and Asians experience the highest amount of daytime sleepiness of the four races,” said Mercedes R. Carnethon, associate professor of preventive medicine at Northwestern University Feinberg School of Medicine.
Carnethon will present the research June 13 at SLEEP 2012, the 26th annual meeting of the Associated Professional Sleep Societies (APSS) in Boston.
These racial/ethnic differences in sleep persisted, even when researchers took into account the participants’ cardiovascular disease risk (CVD) factors and education levels, Carnethon said. In previous studies, CVD has been associated with shorter and poor quality sleep, and persons with less education and fewer financial resources often suffer the worst sleep.
“The link between sleep and cardiovascular risk factors, such as obesity and diabetes, is known to vary by race and ethnic group,“ Carnethon said. “This study suggests race differences in sleep characteristics are not completely explained by these cardiovascular risk factors or by differences in socioeconomic resources.”
Here are highlights from the research, with the results adjusted for age, sex, education, body mass index, hypertension and diabetes:
- Average length of sleep per day varied by race:
-White: 7.4 hours
-Asian: 6.9 hours
-Hispanic: 6.9 hours
-Black: 6.8 hours
- Sleep quality, which is impacted by indicators such as waking during the night after initially falling asleep, was more of a problem for black versus white participants. There were minimal differences in Asian or Hispanics versus whites when it comes to sleep quality.
- Black, Asian and Hispanic participants reported more daytime sleepiness than white participants, with Asians experiencing the highest amount of daytime sleepiness.
The study of more than 500 randomly selected Chicago-area men and women who did not suffer from sleep disorders measured sleep using in-home wrist monitors and queried sleep quality using surveys. Previous studies have typically relied on self-reports of sleep only and usually included people with known sleep disorders, Carnethon said.
“The monitors were worn on the wrist and recorded movement associated with sleeping or waking,” Carnethon said. “The monitor has a computer on board, and we downloaded the data in order to calculate an average sleep duration over seven days.”
More studies are needed to investigate the role race plays in sleep, but Carnethon said no matter your ethnic background, you should take your sleep seriously.
“Every night you should engage in a regular calming bedtime routine that includes decreasing screen time with phones, TVs and computers and allows you to sleep a full, quality, seven to nine hours,” she said.
The National Heart, Lung, and Blood Institute at the National Institutes of Health 4 R01 HL092140‐03 funded this study.