Leg movements in sleep may contribute to risk of stroke and heart disease
Talk to your doctor about overall risk reduction
Sunnybrook and University of Toronto researchers have uncovered links between sleep-related leg movements and stroke, heart disease and mortality in two new studies published this month in the journal SLEEP.
In one study, involuntary repetitive movements in the hip, ankle and big toes during sleep — known as periodic limb movements (PLMs) — were associated with silent strokes in the brain, which appear as bright white spots on MRI brain scans.
In patients who had experienced a first-ever minor stroke or transient ischemic attack (TIA or “mini stroke”), those with more PLMs on an overnight sleep study were shown to have a greater quantity of white matter lesions visualized on neuroimaging. These white matter lesions are known to predict an increased risk of future stroke, dementia and death.
“What this tells us is that PLMs may be a risk factor for, or marker of, silent cerebrovascular disease in the brain. Future work needs to explore whether PLMs could be a novel target for us in our efforts to prevent stroke,” says Dr. Mark Boulos, principal investigator of the study and a sleep and stroke neurologist at Sunnybrook.
It is thought that the involuntary disruptive limb activity at night gives rise to significant nocturnal fluctuations in heart rate and blood pressure, and may result in daytime hypertension. PLMs are also associated with increased markers of inflammation and may increase the risk of plaque formation in the arteries and rupture.
“We’ve known that stroke can lead to PLMs, however, mounting evidence is starting to suggest that PLMs themselves may also contribute to the development of cerebrovascular disease,” says Dr. Brian Murray, co-lead investigator of the study and director of the sleep lab at Sunnybrook.
In a second study, sleep researchers evaluated an association between Restless Legs Syndrome (RLS) and/or PLMs in sleep and all-cause mortality and incident cardiovascular events, this time through a systematic review of studies dating back to 1947.
“While evidence was limited, there appeared to be a significant association between PLMs and risk of cardiovascular events,” says Boulos, senior author of the second study.
“This work is exciting because it sheds light on the potential importance of PLMs, and adds to our emerging recognition of the importance of sleep for long-term brain health,” says Dr. Richard Swartz, senior author of the first paper and Medical Director of the North & East GTA Regional Stroke Program at Sunnybrook.
“PLMs may be among many factors that could contribute to stroke or heart risk, but the link to vascular disease remains under-investigated. It’s best to talk to your doctor about overall risk reduction in the management of good brain and heart health,” says Dr. Sandra Black, Brill Chair of Neurology.