Only about percent of the women without RLS had high blood pressure, the researchers said.
The link between restless legs syndrome and increased blood pressure remained even after the researchers took into account the women's age, weight, smoking, and stroke or heart attack. However, the overall differences in blood pressure were small, the authors stressed, and more research is needed to confirm the findings.
"Because this is a cross-sectional study, we don't know which condition -- restless legs syndrome or hypertension -- comes first," Gao said. "But one possibility is that women with restless legs syndrome are more likely to develop high blood pressure in the future. However, we should be very cautious to reach such a conclusion as it should be supported by a prospective study," he said.
Earlier studies in men also found a link between restless legs syndrome and high blood pressure, the researchers noted.
Dr. Domenic Sica, professor of medicine and pharmacology and director of the Blood Pressure Disorders Unit at Virginia Commonwealth University in Richmond, and co-author of an accompanying journal editorial, noted that interrupted sleep can affect blood pressure.
"If you didn't sleep well and you measured your blood pressure and you were anxiety-prone, the pressure would probably be higher," he said. "Sleep can help anxiety, but if you don't sleep you never have enough rest to bring your blood pressure down at night, which is what it's supposed to do. Blood pressure is supposed to drop about 20 percent at night."
Restless legs syndrome can cause blood pressure to be chaotic at night, Sica said. Still unknown is how treating RLS would affect blood pressure, he said.
If RLS is treated, one may feel better the next day after getting uninterrupted sleep, Sica
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