The Role of Dopamine
Men with RLS who had five to 14 restless leg episodes a month were 16% more likely to report ED than men without RLS; men with 15 or more RLS-related episodes a month were 78% more likely to report having problems getting or maintaining an erection.
The study appears in the January issue of the American Academy of Sleep Medicine journal Sleep.
If RLS and ED are related, the chemical dopamine, which helps regulate both movement and mood, may be the common link.
A shortage of natural dopamine in the brain is believed to play a role in Parkinson's disease and restless legs syndrome; drugs that activate brain receptors that produce dopamine are used to treat both conditions.
Low dopamine levels are also thought to be a contributing factor in erectile dysfunction.
Another potential explanation for the observed association may be lack of sleep.
People with RLS commonly experience sleep deprivation due to their involuntary nighttime limb movements, and sleep deprivation is known to decrease circulating testosterone levels, which can lead to ED.
"Anything that disrupts sleep can cause ED," says David Schulman, MD, MPH, who directs the Emory Sleep Disorders Laboratory in Atlanta. "I don't think it is possible in a study like this one to adjust for that."
Schulman says more study is needed to determine if restless legs syndrome and erectile dysfunction share a common cause.
"I don't look at this as something that will change the way I or anyone else practices medicine right now," he says.