Restless legs syndrome

People who experience these symptoms describe a crawling sensation deep inside their legs, as though insects are moving around, or tingling, pulling, or aching. It is an “unpleasant sensation” that is difficult to pin down in a few words, followed by an urge to keep moving the legs rather than leaving them still. Some people feel it in their arms or torso as well as their legs. The condition is also called “Willis-Ekbom disease,” after Karl Ekbom, the Swedish physician who characterized it, and Thomas Willis, a 17th-century English physician.

Four features are commonly described together when defining the condition.

1. An urge to move the legs occurs along with unpleasant sensations. 2. Symptoms begin or worsen during rest or inactivity. 3. Movement, such as walking or stretching, brings partial or temporary relief. 4. Symptoms are worse in the evening and at night.

Many people also report that this discomfort arises in situations where they must sit for a long time, such as at the cinema, on a plane, or during a lengthy meeting.

The cause is not fully understood. The most widely discussed explanation is the relationship between iron in the brain and dopamine signaling. Relatively low iron levels have been observed in brain regions that regulate movement and sensation, such as the substantia nigra and thalamus. This explanation holds that these low levels affect the balance of dopamine signaling involved in movement control. Several factors, including genetic predisposition, pregnancy, kidney function, and iron status, are understood to contribute together.

The condition is therefore understood in relation to characteristics of the nervous system that regulates sensation and movement, rather than a problem with the leg muscles themselves.

The two are easy to confuse because both involve leg discomfort at night, so many people search for this condition alongside nocturnal leg cramps.

“My legs feel crawly before bed, and I keep wanting to move them” and “My legs are swollen and heavy after standing for a long time” can both be grouped under “leg discomfort,” but they describe different experiences.

The first describes a sensation accompanied by an urge to move the legs. It is noticeable during inactivity, especially in the evening and during rest, and movement brings temporary relief. The second is closer to swelling and heaviness caused by slower return flow through the veins and lymphatic system. It increases with longer periods of standing or sitting and subsides when the legs are elevated or when walking. In this case, reading evening leg swelling may also help.

Here are some clues that may help distinguish them.

• If swelling and heaviness are visibly apparent and increase in proportion to time spent standing or sitting, the discomfort is more likely related to circulation.
• If the urge to move arises in the evening and during rest regardless of activity level, and movement brings immediate relief, it is closer to the sensation described in this article.

Some people experience both, so rather than drawing your own conclusion, try keeping a record of what you notice in your body to use when speaking with a professional.

• Try going to bed and getting up at consistent times. A lack of sleep can make the unpleasant sensations feel more intense (see Sleep hygiene).
• Try cutting back on caffeine, alcohol, and smoking in the evening. Many people try reducing caffeine from the evening onward and observe how their body responds.
• Get some gentle movement during the day. Moderate exercise, such as walking, is helpful. However, it is best to avoid vigorous exercise just before bed.
• Relax your legs before bed. Try soaking your legs in warm water, or gently stretching and massaging your calves and thighs.
• When the unpleasant sensations arise, get up and walk. A short walk or shaking your legs can bring considerable relief compared with forcing yourself to endure it while lying down.
• A blood test can show your iron status. Rather than taking iron supplements on your own, have your levels checked and discuss them with a professional.

• Discomfort makes it difficult to fall asleep almost every night
• Daytime sleepiness and fatigue become severe enough to affect daily life
• Symptoms first appear during pregnancy or become progressively worse
• Symptoms change after a change in medication

If any of these apply, speak with a neurologist or a professional who assesses sleep problems. It helps to bring notes on when you usually feel discomfort and what relieves it.