Restless Legs Syndrome May Boost Blood Pressure

Disrupted sleep might cause the hypertension, expert says

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MONDAY, Oct. 10 (HealthDay News) -- Middle-aged women who suffer from a common condition called restless legs syndrome may be at increased risk of high blood pressure, U.S. researchers report.

Restless legs syndrome is a sensory motor disorder that causes intense, unpleasant leg sensations, and an irresistible urge to move the legs, often at night. The condition, which may affect between 5 to 15 percent of U.S. adults, can disrupt sleep and cause daytime drowsiness.

"For those who experience restless legs syndrome symptoms, please consult your doctor regarding this issue," said lead researcher Dr. Xiang Gao, an assistant professor of medicine at the Harvard Medical School. "The risk of hypertension can be substantially reduced by following a healthy life style, including a healthy diet, regular physical activity, and keeping optimal body weight," he added.

Unabated, hypertension, also known as high blood pressure, can have dire consequences. In 2006, it contributed to 326,000 deaths in the United States, according to background information in the study, published online Oct. 10 in Hypertension.

For the study, Gao's team collected data on almost 98,000 women, averaging about 50 years of age, who took part in the Nurses Health Study II. In 2005, the women were asked about symptoms that could indicate restless legs syndrome (RLS) and also about their blood pressure.

Specifically, they were asked if they had unusual crawling sensations, or pain combined with motor restlessness plus an "urge to move." Women with five or more episodes a month were considered to have RLS, and more than 65,500 were included in the final analysis.

The researchers found a significant connection between RLS and blood pressure. The worse a woman's RLS, the higher her blood pressures, they reported.

More than one-quarter (26 percent) of the women with five to 14 incidents of RLS a month had high blood pressure, according to the study, an among women with 15 or more episodes a month, one in three had high blood pressure.

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 said. "But whether that translates into blood pressure reduction remains the million dollar question," he said.

SOURCES: Xiang Gao, M.D., Ph.D., assistant professor of medicine, Harvard Medical School, Boston; Domenic Sica, M.D., professor of medicine and pharmacology, director, Blood Pressure Disorders Unit, Virginia Commonwealth University, Richmond, Va.; Oct. 10, 2011, Hypertension, online

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