Swollen feet can be a sign of something as simple as standing too long or as serious as heart, kidney, or liver disease. Roughly 1 in 5 Americans over age 65 have lower-limb swelling at any given time, making it one of the most common health complaints in older adults. The cause depends on whether the swelling affects one foot or both, how quickly it appeared, and what other symptoms come with it.
Heart, Kidney, and Liver Problems
When both feet swell gradually over days or weeks, the most important causes to rule out are problems with major organs. Each one disrupts fluid balance in a different way, but the end result is the same: excess fluid pools in your lower body because gravity pulls it there.
In congestive heart failure, the heart’s pumping power weakens and blood backs up in the veins of your legs, ankles, and feet. You may also notice swelling in your abdomen, and fluid can build up in the lungs, causing shortness of breath. If your feet swell and you’re also winded climbing stairs or lying flat, that combination points strongly toward a heart issue.
Kidney disease causes swelling because damaged kidneys can’t clear excess fluid and salt from your blood efficiently. The swelling typically shows up in the legs and around the eyes. A specific type of kidney damage called nephrotic syndrome causes protein to leak out of the blood, which pulls even more fluid into surrounding tissue.
Liver cirrhosis leads to fluid buildup in the abdomen (called ascites) and in the legs. If your belly looks distended alongside swollen feet, liver disease is a likely contributor, especially in people with a history of heavy alcohol use or chronic hepatitis.
Blood Clots in the Leg
Swelling in only one foot or leg is a different situation. The most concerning cause is a deep vein thrombosis (DVT), a blood clot in a deep vein, usually in the calf or thigh. DVT symptoms include leg pain or cramping that often starts in the calf, skin that turns red or purple, and a feeling of warmth in the affected leg. Some DVTs produce no noticeable symptoms at all, which is part of what makes them dangerous. A clot can break loose and travel to the lungs, becoming a life-threatening emergency called a pulmonary embolism.
If one leg suddenly swells and feels warm or painful, especially after a long period of sitting (a car trip, a flight, bed rest after surgery), seek medical attention promptly.
Chronic Venous Insufficiency
Chronic venous insufficiency (CVI) is one of the most common reasons for long-term foot and ankle swelling. It develops when the valves inside leg veins weaken over time, allowing blood to flow backward and pool in the lower legs. You may notice visible varicose veins, spider veins, or skin changes near the ankles: darkening, thickening, or in advanced cases, open sores near the inner ankle. CVI tends to worsen gradually and is more common in people who stand for long hours, are overweight, or have a family history of vein problems.
Lymphedema
If your swelling doesn’t leave a dent when you press on it, the cause may be lymphedema rather than standard fluid retention. Lymphedema happens when the lymphatic system, which normally drains fluid from tissues, is damaged or blocked. It often develops after cancer surgery or radiation that removes or damages lymph nodes, though it can also occur on its own.
One reliable way to distinguish lymphedema from other types of swelling: try to pinch a fold of skin on the top of your second toe. If the skin is too thick and tight to pinch, that’s a hallmark of advanced lymphedema. Over time, the affected skin may become rough, thickened, or develop a warty texture.
Medications That Cause Swelling
Several common medications list foot swelling as a side effect. The most frequent culprits are calcium channel blockers (often prescribed for high blood pressure), which can cause noticeable ankle swelling in a significant number of users. Other drug classes that commonly cause fluid retention include:
- Corticosteroids like prednisone
- Hormone therapies including estrogen, progesterone, and testosterone
- Other blood pressure drugs such as beta blockers, hydralazine, and clonidine
- NSAIDs (common over-the-counter pain relievers like ibuprofen and naproxen)
If your feet started swelling shortly after beginning a new medication, that timing is worth mentioning to your prescriber. Switching to a different drug in the same class often resolves the problem.
Pregnancy and Preeclampsia
Some degree of foot swelling is normal during pregnancy, particularly in the third trimester, because the growing uterus puts pressure on veins that return blood from the legs. Hormonal shifts also cause the body to retain more fluid.
The concern is when swelling appears suddenly or severely after 20 weeks of pregnancy, especially alongside headaches, vision changes, or upper abdominal pain. This pattern can signal preeclampsia, a condition defined by high blood pressure (140/90 mmHg or above) and protein in the urine. Preeclampsia affects both mother and baby and requires close medical monitoring. The World Health Organization identifies it as a leading cause of maternal complications worldwide.
Everyday Causes
Not all foot swelling signals a medical problem. Gravity alone can cause fluid to settle in your feet after a long day of standing or sitting. Hot weather dilates blood vessels and increases pooling. Eating a very salty meal can temporarily tip your body’s fluid balance. These causes are typically mild, affect both feet equally, and resolve overnight or after elevating your legs.
Excess body weight also increases the pressure on veins in the legs, making swelling more common and harder to resolve. Injuries like sprains or fractures cause localized swelling from inflammation, which is usually obvious from the pain and circumstances.
Pitting vs. Non-Pitting Edema
A quick self-check can tell you something useful about your swelling. Press your thumb firmly into the swollen area for a few seconds, then release. If the skin holds a visible dent (a “pit”), that’s pitting edema, which is associated with heart failure, kidney problems, venous insufficiency, and DVT. Healthcare providers grade the severity on a 1 to 4 scale based on how deep the dent is and how long it takes to bounce back. A grade 1 pit is just 2 millimeters deep and rebounds immediately. A grade 4 pit is 8 millimeters deep and takes two to three minutes to fill back in.
If the skin doesn’t pit at all and feels firm or rubbery, that points toward lymphedema or, less commonly, thyroid disease.
Managing Mild Swelling
For everyday swelling without other concerning symptoms, a few strategies help. Elevating your feet above heart level for 15 to 20 minutes several times a day lets gravity work in your favor. Reducing sodium intake makes a real difference: the WHO recommends staying under 2,000 mg of sodium per day (just under a teaspoon of salt), though the average American consumes well over that amount. Compression stockings provide graduated pressure that helps push fluid back up toward the heart. Low-pressure stockings (under 20 mmHg) are available without a prescription and work well for mild swelling. Medium-pressure stockings (20 to 30 mmHg) are typically recommended for chronic venous insufficiency or more persistent edema.
Regular movement matters too. Walking activates the calf muscles, which act as a pump to push blood upward through the veins. If your job keeps you seated or standing in one place, even brief walking breaks every hour can reduce end-of-day swelling noticeably.
Warning Signs That Need Prompt Attention
Swollen feet paired with certain other symptoms suggest something that needs evaluation sooner rather than later. Shortness of breath alongside swelling can indicate heart failure or a blood clot that has reached the lungs. Swelling in one leg with warmth, redness, or calf pain raises concern for DVT. Puffy eyes combined with swollen feet may point to kidney disease. Sudden, severe swelling during pregnancy with headache or vision changes warrants immediate evaluation for preeclampsia.
Swelling that develops gradually over weeks and doesn’t improve with elevation or reduced salt intake also deserves a medical workup, even if you feel fine otherwise. Blood tests, an ultrasound, or a simple urine test can usually narrow down the cause quickly.