Restless legs syndrome (RLS) is the overwhelming urge to move the legs, usually in the evening and at night, that's temporarily relieved by moving and worst when resting. It's common, it's real, and it's often treatable. The single most important thing to check is iron status: guidelines from the American Academy of Sleep Medicine recommend testing iron studies in everyone with significant RLS, because iron deficiency — even mild — drives the condition in many people, and treating it can help. Causes also include genetics, pregnancy, certain medications, and conditions like kidney disease. A doctor can sort it out; the earlier the better, because it's very treatable.
Some sleep problems are hard to describe. Restless legs syndrome is the one where the description comes out wrong and people sound neurotic — 'my legs just... want to move.' But if you've felt it, you know it's unmistakable: a crawling, creeping, aching discomfort deep in the legs that's unbearable when you're still, especially at night, and only relieved by moving. It's real, it's common, and crucially — it's often very treatable. The first step is understanding what it is and what drives it.
What RLS actually feels like
The defining features are surprisingly specific. The urge to move the legs comes with an unpleasant sensation that's hard to locate but distinctly uncomfortable — tingling, crawling, pulling, aching. It's worst in the evening and at night. It comes on or gets worse when you're resting, sitting or lying still. And moving — stretching, walking, kicking — brings temporary relief. Put those together and you have the classic picture: fine all day, miserable on the sofa, desperate in bed. That timing is exactly why RLS wrecks sleep, and why people often describe it as 'my legs won't let me sleep.'
What causes it: the iron connection
Here's the part most people never hear. The single most important driver in many cases is iron — not the dramatic 'take iron' fad, but a genuine biological link. Brain iron deficiency is implicated in RLS, and it can be present even when a standard blood test looks 'normal', because the relevant marker (ferritin) has a different threshold in RLS than for general health. The current American Academy of Sleep Medicine guideline is explicit: everyone with clinically significant RLS should have iron studies checked. That's not optional nice-to-have — it's the standard of care, because treating iron deficiency is often the most direct route to improvement, and because the treatment differs completely depending on what the blood work shows.
Iron isn't the only cause. RLS runs in families (there's a real genetic component), it's very common in pregnancy (especially in the third trimester, usually easing after birth), and it can accompany kidney disease, iron deficiency from any cause, and some medications. Sometimes there's no obvious trigger at all. But the practical starting point is always the same: get the iron checked.
The single most useful thing you can do for RLS is get your iron studies checked — the AASM recommends it for everyone with significant symptoms. Brain iron deficiency drives RLS in many people, and it can hide behind a 'normal' blood count.
RLS in pregnancy
Restless legs is strikingly common in pregnancy — studies suggest a substantial share of pregnant women experience it, particularly in the last trimester — and it usually improves or resolves after delivery. It's thought to relate to iron metabolism, hormones, and folate changes in pregnancy. The good news is that mild pregnancy RLS often responds to the non-drug measures below. Because supplements during pregnancy need to be handled with care, that's a conversation for your obstetric care team rather than self-directed supplementing.
What actually helps
The treatment ladder, roughly in order, starts with things you control and escalates to prescription care:
- Get iron studies checked — first. If ferritin is low, iron supplementation is the evidence-backed first move; a 2025 meta-analysis of randomized trials found iron improved RLS symptom scores and sleep. This is a doctor-led decision, because 'low' in RLS is defined differently and dosing matters.
- Cut the classic triggers. Caffeine, alcohol, and some medications (including certain antihistamines and antidepressants) are known to worsen RLS — worth a hard look in the weeks around when symptoms got worse.
- Move deliberately before bed. Moderate exercise helps some people; a short walk or gentle stretching before bed is low-risk to try.
- Use the relief reflex. Heat (a warm bath or compress) and massage are simple comfort tools when the urge hits.
- See a doctor for the prescription tier. If lifestyle and iron aren't enough, there are evidence-based medications — but these genuinely need a doctor's supervision, because the older first-line ones (dopamine agonists) carry a risk of 'augmentation', where symptoms get worse and earlier with long-term use. Modern prescribing is more careful about this.
When to see a doctor
See a doctor if the urge to move your legs is frequent (several nights a week), disruptive to sleep, or getting worse. RLS is very treatable, and the earlier it's identified the less sleep it steals — and there's no reason to live with it for years. It's especially worth raising the conversation if you're pregnant, if you have kidney disease, or if the symptoms came on alongside a new medication. Don't self-diagnose from a list — the doctor will want to rule out mimics (cramps, nerve issues, positional discomfort) and check the iron.
Where SleepTrace fits
RLS shows up in your night whether you're aware of it or not: fragmented sleep, lots of movement, long stretches awake in the evening hours. SleepTrace records your night with just your iPhone and shows your sleep stages and the sounds and motion in them — so you can see how broken the night really is, and track whether treatment is helping. If you're not sure restless legs is the culprit, a few recorded nights are worth more than a vague sense that 'I sleep badly.' And if a partner says you also snore or pause breathing, that's a separate thread worth pulling too — read signs of sleep apnea in women or what causes snoring next.
References
- Winkelman JW, Berkowski JA, DelRosso LM, et al. Treatment of restless legs syndrome and periodic limb movement disorder: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med (2025). Europe PMC
- Allen RP, Picchietti DL, Auerbach M, et al. Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children. Sleep Med (2018). Europe PMC
- Mahmoud A, Salamah HM, Alshaker H, et al. Efficacy and safety of iron supplements for restless leg syndrome: a systematic review, meta-analysis, meta-regression, and trial sequential analysis of randomized controlled trials. Proc (Bayl Univ Med Cent) (2025). Europe PMC
SleepTrace is a wellness app, not a medical device. This article is general information, not medical advice. If your symptoms are frequent, severe or worrying, please talk to a doctor.
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