Restless legs at night happen because of a natural dip in dopamine activity that occurs in the evening, combined with the stillness of lying down. If you’re prone to restless legs syndrome (RLS), your brain’s dopamine signaling is already off-balance, and that nightly drop pushes it past a threshold where your legs start demanding movement. About 7 to 10 percent of the population deals with this, and the timing is not random: it’s tied to your body’s internal clock.
Why Symptoms Peak at Night
Dopamine, the chemical messenger that helps regulate movement, follows a 24-hour cycle in your brain. Levels rise in the morning and hit their lowest point in the late evening and overnight. For most people, this dip goes unnoticed. But in people with RLS, the brain appears to overproduce dopamine during the day, which causes the receiving end of the signaling chain to dial down its sensitivity. When dopamine naturally drops at night, those desensitized receptors can’t pick up enough of the signal, creating a functional shortage right when you’re trying to sleep.
This isn’t just about dopamine levels being “low.” The underlying problem is more like a miscalibration: too much dopamine production paired with reduced ability to use it. The result is that motor circuits in your brain become overexcitable. Research points to an increase in excitatory nerve pathways rather than a failure of calming ones, which is why your legs feel like they need to move rather than simply feeling weak or numb. The urge peaks during the falling phase of your core body temperature cycle, which coincides with the hours just before and after you fall asleep.
Iron’s Role in the Problem
Iron is essential for producing dopamine, and low iron stores are one of the most common and fixable triggers for restless legs. The threshold that matters here isn’t the same one used to diagnose anemia. You can have “normal” iron levels on a standard blood test and still have enough of a shortfall to trigger RLS. Specialists look at ferritin, a protein that reflects your body’s iron reserves, and consider levels at or below 75 ng/mL a potential contributor to restless legs. For people who need faster relief, some treatment protocols target ferritin levels below 100 ng/mL.
This is worth knowing because many people with mild or borderline iron deficiency never get flagged. If your ferritin is 40 ng/mL, your doctor might tell you it’s within the normal range, but it could still be driving your nighttime leg symptoms. Getting your ferritin checked specifically, not just a basic iron panel, is one of the most useful first steps. Iron supplements should only be taken after testing, since excess iron causes its own problems. Taking iron with vitamin C on an empty stomach every other day improves absorption.
Genetics and Family History
RLS runs in families. Twin studies estimate that genetics account for 54 to 69 percent of the risk, making it one of the more heritable neurological conditions. Researchers have identified at least 19 genetic regions linked to RLS, with the strongest signal coming from a gene called MEIS1, which plays a role in nervous system development. Another gene, BTBD9, has been linked to both RLS and iron metabolism in the brain.
That said, all the genetic variants discovered so far explain less than 10 percent of the inherited risk, meaning there’s still a lot scientists don’t understand about why it clusters in families. If one or both of your parents had restless legs, your chances are significantly higher, and your symptoms may have started earlier in life. People with a strong family history tend to develop RLS before age 45, while those without a genetic predisposition more often develop it later, usually tied to another medical condition.
Medical Conditions That Trigger Restless Legs
Several health conditions make restless legs more likely, even in people who’ve never experienced them before. Kidney disease is one of the strongest associations: roughly 27 percent of people with end-stage kidney disease have RLS, and interestingly, the duration of dialysis doesn’t seem to make the symptoms better or worse. The mechanism likely involves impaired iron handling and changes in dopamine metabolism that come with chronic kidney dysfunction.
Pregnancy is another major trigger. About 21 percent of pregnant women develop restless legs, typically in the third trimester when iron demands are highest and hormonal shifts are most dramatic. The good news is that roughly 80 percent of those cases resolve completely after delivery. The remaining 20 percent who still have symptoms 12 weeks postpartum may have had an underlying predisposition that pregnancy unmasked.
Peripheral neuropathy, thyroid problems, and diabetes can also contribute. In these cases, treating or managing the underlying condition often reduces the restless legs as well.
Medications That Make It Worse
Some of the most commonly used over-the-counter and prescription drugs can trigger or worsen restless legs, and many people don’t realize the connection. Antihistamines are a frequent culprit. The same ingredient that makes allergy pills and OTC sleep aids cause drowsiness, diphenhydramine, blocks dopamine activity in a way that intensifies RLS. Melatonin supplements can also worsen symptoms for some people.
Among prescription medications, certain antidepressants are known to aggravate restless legs, with mirtazapine being one of the most commonly reported. Alcohol, caffeine, and nicotine all have the potential to make symptoms worse too. If your restless legs started or worsened around the time you began a new medication, that’s worth discussing with whoever prescribed it.
What Actually Helps
The most effective relief depends on what’s driving your symptoms. If low iron is involved, correcting it can dramatically reduce or eliminate the problem. Beyond that, a combination of lifestyle changes and physical strategies works for many people.
Moderate, regular exercise reduces RLS symptoms for most people, but the timing matters. Working out too late in the evening or pushing too hard can backfire and make the restlessness worse. Aim for earlier in the day at a moderate intensity.
Caffeine is worth cutting entirely if you haven’t tried it. That includes coffee, tea, soda, and chocolate. Even moderate caffeine intake can be enough to amplify symptoms, and the effect can persist for hours after your last cup.
For in-the-moment relief, physical pressure and stimulation can help interrupt the urge to move. Foot wraps designed for RLS apply steady pressure to the underside of the foot, and vibrating pads placed against the back of the legs have shown benefit. Prescription nerve-stimulation devices that target a nerve near the knee are another option. Keeping your sleeping environment cool and sticking to a consistent sleep schedule also helps, since anything that disrupts your circadian rhythm can amplify the dopamine timing problem that drives nighttime symptoms.
For persistent or severe cases, prescription medications targeting the nervous system’s excitability pathways have become the preferred first-line treatment, largely replacing older dopamine-boosting drugs that tended to make symptoms worse over time. If lifestyle changes and iron correction aren’t enough, that’s a conversation worth having with your doctor.