April 9, 2007 -- Early research suggests a possible link between restless legs syndrome and heart disease.
Periodic leg movement during sleep, which is a characteristic of restless legs syndrome (RLS), led to increased blood pressure among patients participating in a newly reported study from the University of Montreal.
Blood pressure increases were greatest among older patients with RLS, suggesting that these patients may be particularly vulnerable, says cardiologist Paola Lanfranchi, MD, MSc, one of the researchers in the study.
Lanfranchi says the blood pressure elevations recorded during the sleep study were similar to those seen in patients with moderate sleep apnea, which is a known risk factor for heart disease.
“We are learning more and more about the important role of sleep disturbances in heart disease,” she tells WebMD. “We have seen this with other sleep disorders. This study shows that we need to look closer at restless leg.”
BP Recorded During Sleep
Restless legs syndrome is considered both a neurological and sleep disorder because patients typically experience the worst symptoms when they lie down to sleep.
More than 80% of patients experience involuntary leg twitching or jerking movements during sleep that typically occur at intervals of 20 to 40 seconds.
As a result, patients may repeatedly awaken during the night and, like people with other sleep disorders, they many experience daytime fatigue, impaired memory, and concentration problems.
RLS patients have also been shown to have an increased risk for high blood pressure (hypertension) and heart disease in several previous studies, but it has not been clear if the sleep disorder contributed to the cardiovascular disease or visa versa, Lanfranchi says.
In an effort to answer this question, the University of Montreal researchers asked 10 patients with untreated RLS to spend the night in a sleep lab, where researchers monitored leg movements and blood pressure changes.
None of the patients had heart disease or hypertension, and none were taking blood pressure-lowering drugs.
Lanfranchi and colleagues found that blood pressure rates linked to sleep-related periodic leg movement rose by an average of 22 points for the systolic reading (top number of a blood pressure reading) and 11 points for the diastolic reading (bottom number of blood pressure reading).
They concluded that this degree of elevation, occurring frequently over time, could lead to heart and blood vessel damage. Their findings are published in the April 10 issue of the journal Neurology.
The study did not include RLS patients with heart disease, but these patients may have the greatest risk, Lanfranchi says.
“Blood pressure elevations during the night could be very harmful to the already damaged hearts of these patients,” she says. “Clinicians taking care of these patients need to be aware of this.”
Can RLS Drugs Lower Risk?
All agree that more research is needed to confirm the findings and to determine if medications used to treat RLS can reduce the potential risk.
Sleep disorders expert Merrill Mitler, PhD, tells WebMD that this is unlikely because the available drug treatments have only a modest impact on symptoms.
Mitler is program director for the National Institute of Neurological Disorders and Stroke.
“There are certainly no treatments that can make restless leg go away,” he says. “But there are behavioral and conceptual approaches that can help patients learn to live with this condition.”
He adds that the new study, while small, makes a strong case for a link between restless legs syndrome and heart disease.
But University of Maryland School of Medicine neurology professor William J. Weiner, MD, says it will take much more research to convince him.
Weiner is the director of the Maryland Parkinson’s Disease and Movement Disorders Center in Baltimore.
“This study is an interesting beginning, but this was a very small study and these patients weren’t followed to see if they developed heart disease,” he tells WebMD. “The conclusion that these blood pressure fluctuations contribute to heart disease is a very big leap.”