Bedtime is far from relaxing for women with this common condition.
Restless legs syndrome (RLS) is a sensory-motor disorder that causes an irresistible urge to move the legs, often accompanied by an uncomfortable "creepy-crawly" sensation. RLS affects 3% to 5% of adults and is twice as common in women as in men. Symptoms typically flare at night, just as you're settling down in bed, but they may also arise when you're resting in a chair. RLS not only causes discomfort and distress, but can also wreak havoc on sleep, causing daytime sleepiness and mood changes. Fortunately, certain lifestyle strategies can help you manage milder forms of RLS, and several medications can provide relief for more serious symptoms.
There's a common mistaken belief that RLS refers to the jittery, leg-bouncing movements some people make when they're anxious or overstimulated. Partly because of this, the RLS Foundation, a nonprofit organization that provides information about the disorder, is lobbying to change its name officially from RLS to Willis-Ekbom disease (see "What's in a name?"). According to the foundation, the term "restless legs" trivializes a problem that can have a "severe and profound" impact on sleep and daily functioning.
What's in a name?
English physician Sir Thomas Willis (1621–75) first described the condition now known as restless legs syndrome (RLS) in 1672. He wrote of "leapings and contractions" so intense that sufferers "are no more able to sleep than if they were in a place of the greatest Torture." Other descriptions appeared in the medical literature in the 19th century, including one that attributed the problem to hysteria, a diagnosis that encompassed a range of psychological and physical problems. The Swedish neurologist Karl-Axel Ekbom (1907–77) introduced the term "restless legs" in 1944, in an article detailing the disorder's features.
In January 2011, the RLS Foundation voted unanimously to change "restless legs syndrome" to "Willis-Ekbom disease" — to acknowledge these physicians' contributions and to make it clear that the disorder is not simply a collection of symptoms (a syndrome), but a condition (disease) linked to genetic and neurochemical changes.
Symptoms of RLS
People with RLS describe the discomfort as feelings of creeping, prickling, pulling, itching, tugging, or stretching that typically occur below the knees and are felt deep within the legs. In severe cases, the arms are affected as well. Movement provides immediate relief, so people with the condition often fidget, kick, or massage their legs, or get up to pace the floor or perform deep knee bends.
Symptoms tend to worsen at the end of the day and peak at night, often within a half-hour after going to bed. In severe RLS, the symptoms strike earlier in the day — a challenge for people who must sit for a long time, as when attending meetings, performing desk work, or traveling long distances.
What causes RLS?
Primary RLS, the most common form of the disorder, is idiopathic, meaning that it has no known cause. But more than 40% of people with primary RLS have a family history of it, which suggests a strong underlying genetic component. Researchers have found five gene variants that predict a greater likelihood of RLS.
One theory is that primary RLS arises from an imbalance of dopamine, a neurotransmitter with many roles in the body, including the regulation of muscle movement. Some of the medications used to treat RLS work by mimicking the action of dopamine in the brain. RLS can also develop as a byproduct of other medical problems. One of the chief culprits in this secondary form of the disorder is iron deficiency, which may explain why the condition is more common in women.
"Women are more prone to low iron levels, mostly because of blood loss from menstruation," says Dr. John Winkelman, medical director of the Sleep Health Center of Brigham and Women's Hospital and associate professor of psychiatry at Harvard Medical School. Pregnancy, childbirth, and breastfeeding also deplete iron stores.
One small study found that older people with RLS had lower levels of ferritin (the main protein the body uses to store iron), and the lower the ferritin level, the worse the symptoms. Other research has shown lower ferritin levels in the spinal fluid of RLS sufferers and lower iron stores in their substantia nigra (one of the brain's centers for movement control).
People with kidney disease who receive dialysis (a process that filters waste and removes excess water from the blood) have an increased risk of developing RLS. It's also more common in people with diabetic neuropathy (nerve damage caused by diabetes). Multiple sclerosis, Parkinson's disease, and certain rheumatic diseases (rheumatoid arthritis, lupus, and Sjögren's syndrome) may also raise the risk, though the evidence isn't conclusive. Some research has linked varicose veins to RLS, and preliminary studies suggest that treating them (with sclerotherapy injections or laser energy) may ease RLS symptoms, but the evidence so far is not definitive.
Finally, many common drugs can aggravate RLS symptoms, including caffeine, alcohol, and nicotine; the antihistamine drug diphenhydramine (Benadryl), which is found in many over-the-counter cold, allergy, and sleeping pills; prescription antidepressants such as amitriptyline (Elavil), fluoxetine (Prozac), and escitalopram (Lexapro); and antinausea medications, including metoclopramide (Reglan, others) and prochlorperazine (Compazine).
Stand two to three feet from a wall. Step forward with one foot and bend the knee, keeping the back knee straight. Place your hands on the wall for support and push your pelvis forward as far as you comfortably can, keeping your back heel on the floor. Hold for 10 to 20 seconds. Repeat five times on each side.