Restless Legs Syndrome (RLS). Symptoms, Causes, and Helpful Tips

As suggested by its name, Restless legs syndrome (RLS) is a disorder that is characterized by unpleasant and uncomfortable feelings of the lower limbs with an overwhelming urge to move them and change position.

Restless legs syndrome is also sometimes referred to as Willis-Ekbom Disease. It was first described in 1685 by English physician and anatomist Thomas Willis, whose work was built upon almost three hundred years later by Karl-Axel Ekbom in 1960.

Overlooked for a long time, RLS has gained more focus from the medical and research community. However, it still is recognized as being a poorly understood disorder with an unclear pathology, and causes.

Symptoms of RLS

The uncomfortable sensations in the lower limbs that are caused by RLS are at times painful, but can also be described as itching, crawling, or pulling sensations. These sensations predominantly occur during the later hours of the day and at night, which signals a highly significant circadian expression of this disorder.

However, it can also occur at times of rest, for example, sitting for a longer period of time, such as during road trips in a car or traveling in a plane, lying down on the couch to watch a movie, or reading. The unpleasant sensation can occur either in one of the limbs or both, with pains, itches, crawls, and aches being either significantly localized, to the ankle or knee for example, or appearing as an overall feeling in the lower limbs.

Case studies indicate that RLS can also be experienced in phantom limbs, suggesting the neuropsychological component of the disorder. It has been reported that, in the extensive course of the disease, it is possible for the disorder to “spread” to other body parts, such as hands.

Moving the limbs, while walking or stretching, can relieve the uncomfortable sensations temporarily, however they tend to resume either immediately or shortly after the movement stops. Given the RLS occurs mostly during the night and the symptoms are triggered by the falling asleep and resting, it is classified as a sleeping disorder. It can cause both difficulties initiating sleep and awakenings during the night.

Prevalence and risk factors

The estimated prevalence of RLS varies greatly based on population. Overall, the reports indicate that, in the general population, the rates vary from 3.9% to 15%.

It has been suggested that it occurs more commonly in the Western cultures, with the rates between 5.5% to 15% depending on the specific regions, with Europe being the lowest of all, with rates of approximately 5.5%, and the United States having the highest numbers of RLS incidents of 10% to 15%. The reported numbers of cases in Eastern countries are significantly lower, suggesting there might be a cultural or genetic component to RLS.

The prevalence and severity of RLS are associated with aging. It is proposed that the neurodegeneration that occurs in both pathological and healthy aging plays a role in the development and symptoms of RLS.

In addition, it has been observed that the risk of RLS partly depends on gender, with women suffering from it twice as often as men. Given this vast difference in prevalence rates between genders, sex hormones such as estrogen and progesterone, as well as the social roles of gender, are common research targets when investigating the causes and effects of RLS.

Even though the possibility of RLS increases with age, the onset of the disorder can occur anywhere during a person’s lifetime. Population studies indicate that out of all RLS cases, the rates in children are quite low and there are no pronounced differences between boys and girls.

This suggests that female hormonal changes that occur during puberty, pregnancy, and menopause might have a causal link to the RLS. Around 40% of RLS patients report the first symptoms were experienced around or even before the age of 20, making early onset RLS rather frequent.

Causes

To date, there is no single recognized cause for RLS. Research has been focused on several factors:

• Circadian rhythms. Even though it falls under the category of sleeping disorders, RLS is categorized as a neurological sensory disorder. The sensory and motor symptoms of RLS follow the circadian rhythm, with the symptom intensity peak at the body’s lowest temperature and which seems to be relieved as the core body temperature increases as a person wakes up and stays awake. Studies indicate that the sleep hormone melatonin has an inhibiting effect on dopamine, a neurotransmitter involved in movement, resulting in RLS symptoms getting worse.
• Genetics. Research suggests that RLS runs in families, indicating a strong genetic component of the disorder. This is primarily the case in the early onset RLS cases.
• Iron deficiency. It has been suggested that iron is involved or even causes RLS very early on, in the original work of Ekbom. Currently, it is not believed that iron deficiency causes RLS, given that some patients have normal or higher than normal iron levels. However, the link between iron and RLS remains, as several biological studies indicate RLS patients have low iron and ferritin (an iron storage protein in your liver) levels, compared to healthy individuals.
• Pregnancy. This significantly increases the risk of RLS, especially as the pregnancy gets closer to term. Epidemiological studies suggest the risk increases with the number of pregnancies as well. RLS could be caused by hormonal changes, together with the increased demand for iron (which may result in iron deficiency), anxiety, and insomnia, which all commonly occur during the last trimester of the pregnancy.

Helpful tips

You should always consult your physician for official diagnosis and treatment of RLS, regardless if it is a chronic condition or has acute symptoms triggered by pregnancy, menopause, or another life event.

However, there are several things that might help ease the uncomfortable sensations in your limbs:

• Avoid smoking, and other nicotine-containing products such as snuff, chewing tobacco, and patches. It has been shown that nicotine acts as a stimulant and affects the dopaminergic system.
• Moderate exercise done on a regular basis has been shown to improve the symptoms of RLS.
• Sleep hygiene is important.
• Relaxation exercises.
• Hot baths, heating pads or cold compresses. Hot baths or warm compresses more commonly relieve the unpleasant feelings in the limbs, however some people report the low temperature helps them feel better.
• Avoid caffeine, which acts as a stimulant and has been shown to increase the symptoms of RLS.