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According to research by scientists in BWH’s Division of Sleep Medicine, leg movements that follow pauses in breathing during sleep might be a predictor for cardiovascular disease events in elderly males with moderate to severe obstructive sleep apnea.
The National Sleep Foundation reports that more than 18 million adults in the U.S. have sleep apnea—a disorder in which breathing is repeatedly disrupted during sleep. Obstructive sleep apnea, in particular, occurs when muscles in the airway, such as the tongue, block breathing during sleep.
Previous studies have shown that obstructive sleep apnea is a risk factor for high blood pressure and heart disease. A BWH research team led by John Winkelman, MD, PhD, wanted to investigate whether respiratory-related leg movements (RRLM), muscle movements in the leg that follow a sleep apnea episode, may further contribute to heart disease risk.
Researchers analyzed data gathered from the existing Osteoporotic Fractures in Men (MrOS) Study, which included nearly 6,000 participants, whose sleep was monitored at home. Participants completed questionnaires and surveys about their medical history, lifestyle activities and health status.
From the MrOS study, Winkelman and his team examined data from 636 men, with a mean age of 81 years, who recorded moderate to severe sleep apnea and leg movements.
They found that risk for heart attacks and other cardiovascular events increased by 26 percent for every 20 to 25 such leg movements per night. The research team noted that more work needs to be done.
“It is not clear from this data whether the increased risk is due to leg movements being markers of more severe sleep apnea episodes, or whether leg movements are producing greater swings in blood pressure, and therefore, a higher risk for cardiovascular disease events,” said Winkelman. “We plan to do more research to answer such questions.”
Though the answers to these questions are still unknown, the data opens the door to new possibilities for combating heart disease in the future.
“Easily identified features in sleep may be important in predicting future risk of heart disease in those with sleep apnea,” said Winkelman. “If confirmed, we could target aggressive treatment for those with sleep apnea at highest risk of heart disease. Further, we need to see if quieting such leg movements could possibly reduce risk of heart disease for people with sleep apnea.”