FRIDAY, Sept. 21, 2012 (HealthDay News) -- Insomnia is nobody's friend, but new research indicates that those with high blood pressure who struggle to get enough sound sleep are twice as likely to have a resistant case of hypertension as those who sleep well.
Studying more than 230 patients with hypertension, scientists from the University of Pisa in Italy also found that women scored far higher than men on measures of poor sleep quality, and most participants slept six or fewer hours per night. The participants had an average age of 58.
"There are a number of studies demonstrating a relationship between hypertension risk and insomnia and short sleep duration, but no one correlated poor sleep quality with hypertension severity [before]," said study author Rosa Maria Bruno, a doctoral student and research fellow at the Institute of Clinical Physiology-National Council of Research in Pisa.
"The results ... suggest that insomnia in resistant hypertensive patients, particularly women, could be clinically relevant not only for quality of life but also for cardiovascular health and should not be disregarded," she added.
The study is scheduled to be presented Friday at the American Heart Association's High Blood Pressure Research meeting in Washington, D.C.
About 75 million Americans have diagnosed high blood pressure, with 50 million taking anti-hypertensive drugs. But medications don't sufficiently control the condition -- a major risk factor for heart disease -- in 20 percent to 30 percent of those cases, according to the heart association.
High blood pressure is considered resistant if patients are taking three or more hypertension medications but still log blood pressure readings higher than 140/90 mmHg.
Although short sleep duration was highly prevalent in all study participants, women were found to suffer disproportionately from poor sleep quality and depressive symptoms. About 12 percent of participants had experienced previous cardiovascular events, while 8 percent had diabetes and 15 percent were smokers.
Bruno said the research didn't analyze potential reasons why bad sleep may lead to resistant hypertension -- and didn't establish a cause-effect relationship between the two -- but that sleep and cardiovascular disorders are tightly linked. Sleep problems also are related to obesity and diabetes, which contribute to resistance to blood-pressure-lowering drugs, she said.
"We can't exclude that living with a chronic disease, like resistant hypertension, may act as a chronic stressor, causing disruption of sleep," Bruno said.
Dr. Balu Gadhe, an internal medicine specialist with CareMore Medical Group in Cerritos, Calif., said the research highlights the need for good sleep habits, including getting regular exercise to promote peaceful slumber.
"We are all wired up in day-to-day life, where we have multiple stressors in our lives. Our body reacts to those stressors by releasing hormones ... and other chemicals into our bodies that make the organs work harder," he said. "If we're not getting good sleep, we're not getting rest for those organs and eventually they'll start malfunctioning. That's the bottom line, and the only way to do it is not just by getting enough hours of sleep but good quality sleep."
Research presented at scientific meetings has not been peer-reviewed or published, so results should be considered preliminary.
A list of the top 10 things to know about resistant hypertension can be found at the American Heart Association.