Leg aching has dozens of possible causes, ranging from something as simple as overexertion to circulatory problems that need medical attention. The cause usually depends on a few key details: whether the pain is in one leg or both, whether it’s worse with activity or at rest, and how long it’s been going on. Understanding those patterns can help you narrow down what’s happening.
Muscle Strain and Overuse
The most common reason for achy legs is simply working them harder than usual. A long day on your feet, a new workout routine, or even yard work you haven’t done in months can leave your legs sore for days. This type of soreness, known as delayed onset muscle soreness, typically sets in one to three days after the activity and resolves within five days. If your leg pain started after physical exertion and is fading over a few days, this is the most likely explanation.
On the flip side, not using your legs enough can also cause aching. Sitting at a desk for hours, long car rides, or extended bed rest leads to stiffness and a dull ache that improves once you start moving. The fix in both cases is gradual: ease into activity if you’ve been sedentary, and give your muscles recovery time if you’ve overdone it. If soreness from exercise lasts more than a week, it may be a muscle strain rather than normal post-exercise soreness.
Poor Circulation in the Arteries
Peripheral artery disease (PAD) causes leg pain because narrowed arteries can’t deliver enough blood to your leg muscles during activity. The hallmark symptom is called claudication: cramping or aching in the calves, thighs, or hips that starts when you walk or climb stairs and stops when you rest. It’s essentially your muscles running out of oxygen.
PAD pain can range from mild to severe. In early stages, you might only notice it after walking a certain distance. As the condition progresses, the distance you can walk pain-free shrinks. In advanced cases, the aching and cramping can wake you from sleep or occur even while lying down. PAD is most common in people over 50, especially smokers and those with diabetes, high blood pressure, or high cholesterol. If your leg pain reliably appears during walking and disappears within a few minutes of stopping, that pattern is worth discussing with a doctor.
Venous Insufficiency and Varicose Veins
While arterial problems cause pain during movement, vein problems tend to cause pain during stillness. Chronic venous insufficiency happens when the valves inside your leg veins stop working properly, allowing blood to pool rather than flow back toward your heart. The result is a heavy, aching sensation in the legs, particularly after prolonged standing or sitting.
This pooling increases the volume and pressure inside the tissue compartments of your lower legs, which is what produces that characteristic heaviness and throbbing. You might also notice swelling around your ankles, visible varicose veins, or skin changes near your shins. The telltale sign of venous insufficiency is that elevating your legs brings noticeable relief. If propping your feet up for 15 to 20 minutes consistently eases the aching, your veins are likely involved.
Nerve-Related Leg Pain
Nerve problems create a different kind of leg pain. Sciatica, caused by a compressed nerve in the lower back, typically sends shooting or burning pain down one leg, often from the buttock to the calf. It usually affects one side and may worsen with sitting or bending.
Peripheral neuropathy, often linked to diabetes, works differently. It tends to affect both legs in a “stocking” pattern, starting in the feet and gradually moving upward. The sensations include burning, electrical-shock feelings, sharp pain, or a deep ache, sometimes with numbness or tingling layered on top. If your leg aching is accompanied by unusual sensations like pins and needles, burning, or areas of numbness, nerve damage is a possibility worth investigating, especially if you have diabetes or prediabetes.
Electrolyte and Nutritional Deficiencies
Your muscles need specific minerals to contract and relax properly. When levels of magnesium, potassium, or calcium drop too low, the result is muscle cramps, spasms, and a persistent aching feeling. Normal magnesium levels fall between about 1.5 and 2.7 mg/dL, and even mild deficiency can trigger muscle spasms and cramping. Low magnesium also tends to pull potassium and calcium levels down with it, compounding the problem.
You’re more likely to have low electrolytes if you take certain medications (particularly diuretics or acid-reducing drugs), drink alcohol heavily, exercise intensely without replenishing fluids, or have digestive conditions that impair absorption. Dehydration alone can also cause leg aching and cramping. If your legs ache and you’re also experiencing muscle twitches, numbness in your hands or feet, or fatigue, an electrolyte imbalance is worth considering.
Fibromyalgia and Widespread Pain
If your legs ache alongside pain in multiple other parts of your body, fibromyalgia may be a factor. Current diagnostic criteria require pain in at least four of five body regions (which include the left and right legs as separate regions) lasting at least three months, combined with significant fatigue, poor sleep quality, or cognitive difficulties sometimes called “brain fog.”
Fibromyalgia pain is typically widespread and fluctuating. It doesn’t follow the pattern of joint disease or muscle injury. The aching tends to be diffuse rather than pinpointed, and it’s often worse during periods of stress, poor sleep, or weather changes. If your leg aching is part of a bigger picture of body-wide pain and exhaustion, this is a diagnosis to explore.
Arthritis in the Hips, Knees, or Ankles
Osteoarthritis, gout, and rheumatoid arthritis can all produce aching that feels like it’s coming from the leg itself when the source is actually a joint. Hip arthritis commonly refers pain into the thigh or groin. Knee arthritis can make the entire lower leg feel achy and stiff. The distinguishing feature is that the pain tends to center around a joint, worsens with specific movements, and may come with stiffness that’s worst in the morning or after sitting for a while.
Signs That Need Prompt Attention
Most leg aching is not dangerous, but certain patterns signal something more urgent. A blood clot in a deep leg vein, called deep vein thrombosis, requires fast treatment. The warning signs include swelling in one leg (not both), warmth and redness over the affected area, tenderness along the inner thigh or calf, and pain that came on relatively suddenly. One practical comparison: if one calf is noticeably larger than the other, particularly more than 3 cm bigger when measured below the knee, that asymmetry is a strong indicator.
Your risk of a blood clot is higher if you’ve recently been immobilized (long flight, surgery, bed rest for more than three days), have active cancer, have had a clot before, or are on hormonal medications. Leg pain combined with sudden shortness of breath is an emergency, as it may indicate a clot has traveled to the lungs.
Also worth urgent evaluation: leg pain with fever and spreading redness (possible infection), sudden loss of sensation or ability to move the leg, or leg skin that looks pale or blue and feels cold to the touch, which could indicate a severe blockage in blood flow.