- Mar. 11, 2008 —

Science Daily/Duke University Medical Center

Researchers at Duke University Medical Center say they may have figured out why poor sleep does more harm to cardiovascular health in women than in men.

"This is the first empirical evidence that supports what we have observed about the role of gender and its effects upon sleep and health," says Edward Suarez, an associate professor in the department of psychiatry and behavioral sciences at Duke and the lead author of the study. "The study suggests that poor sleep -- measured by the total amount of sleep, the degree of awakening during the night, and most importantly, how long it takes to get to sleep -- may have more serious health consequences for women than for men."

The researchers found that about 40 percent of the men and the women were classified as poor sleepers, defined as having frequent problems falling asleep, taking 30 or more minutes to fall asleep or awakening frequently during the night. But while their sleep quality ratings were similar, men and women had dramatically different risk profiles.

"We found that for women, poor sleep is strongly associated with high levels of psychological distress, and greater feelings of hostility, depression and anger. In contrast, these feelings were not associated with the same degree of sleep disruption in men," says Suarez.

Women who reported higher degree of sleep disruption also had higher levels of all the biomarkers tested. For women, poor sleep was associated with higher levels of C-reactive protein and interleukin-6, measures of inflammation that have been associated with increased risk of heart disease, and higher levels of insulin. The results were so dramatic that of those women considered poor sleepers, 33 per cent had C-reactive protein levels associated with high risk of heart disease, says Suarez.

"Interestingly, it appears that it's not so much the overall poor sleep quality that was associated with greater risk, but rather the length of time it takes a person to fall asleep that takes the highest toll," says Suarez. "Women who reported taking a half an hour or more to fall asleep showed the worst risk profile."

http://www.sciencedaily.com/releases/2008/03/080310131529.htm