Women with coronary heart disease experiencing less than six hours a night may be putting themselves at risk for exacerbating their condition, according to a new study conducted by researchers at the University of California, San Francisco.

Inflammation as a predictor of cardiovascular health is nothing new, said lead author Aric Prather, a clinical health psychologist and assistant professor of psychiatry at UCSF. However, unlike before, scientists now have evidence that inadequate sleep may be driving long-term increases in inflammation levels that in turn may also contribute to the negative consequences often associated with a lack of rest.

Started in 2000, the study included nearly 700 people, the average of men being 66 and women 64. On average, women had higher systolic blood pressure, were more likely to be taking antidepressants, and less likely than men to have a history of taking beta-blockers, statins or other medications used to treat blood pressure and other coronary-related ailments.

All, however, had coronary heart disease, a condition marked by inflammatory activity.

Participants were asked when they first enrolled and then five years later to rate the overall quality of their sleep during the past month.

In doing so, researchers found that poor sleep quality was significantly associated with five-year increases in the biomarkers in women but not men, with women who reported very or fairly poor sleep quality showing a percent increase of indicative markers 2.5 times that of men who said they said equally poorly.

While not completely clear as to why this is the case, the authors of the study hypothesize that since all the women in the study were post-menopausal, the inflammatory activity may be a result of lower levels of estrogen that testosterone, which is at higher levels in men, buffers.

Furthermore, researchers looked at self-reported aspects such as falling asleep or staying asleep, waking up frequent and waking up too early, the latter being especially harmful, based on the study's results. 

In response, 81 percent of women reported that they frequently woke up, versus 78 percent of women. Nearly half of the women said they woke too early, compared to 41 percent among men. Finally, 33 percent of women said they had difficulty falling asleep, whereas only 31 percent of men said the same.

Ultimately, the authors argue that the results could add to the established evidence of the importance of assessing and treating sleep disturbances in high-risk populations, including those with heart disease.