Middle-aged women who slept less than 6 hours a night showed higher levels of inflammation in the body over 5 years. Inflammation is a risk factor for heart attack and stroke.
Poor sleep appears to worsen heart disease and increase heart attack risk by boosting inflammation in the body over time, researchers from the University of California – San Francisco reported.
But guys can breathe a little easier — the findings only held true in women.
The research team followed 626 men and women with coronary heart disease for five years. The average age of the women was 64, and men 66. Inflammation in the body was tracked by measuring levels of three biomarkers: interleukin-6, C-reactive protein and fibrinogen.
Patients were asked to self-report their sleep quality at the beginning and end of the five-year study period.
At the end of the study, women who reported very poor or fairly poor sleep had 2.5 times the increase in inflammation levels as the men who slept poorly. Researchers defined poor sleep generally as less than 6 hours per night.
In particular, waking up too early in the morning was associated with poor sleep quality, and thus inflammation. About half the women in the study reported waking up too early, compared to about 41 percent of men.
Inflammation is thought to play a role in heart attack and stroke, in that it results from the buildup of plaque in the arteries, which the body sees as a foreign substance, according to the American Heart Association.
“Inflammation is a well-known predictor of cardiovascular health,” the study’s lead author Aric Prather, Ph.D., said in a statement released by the university. “Now we have evidence that poor sleep appears to play a bigger role than we had previously thought in driving long-term increases in inflammation levels and may contribute to the negative consequences often associated with poor sleep.”
Researchers speculated that the gender difference may be due to lower estrogen levels in the study’s post-menopausal female subjects, whereas men were protected by higher levels of testosterone.
The study was published Wednesday in the Journal of Psychiatric Research.