When Swelling May Be a Warning Sign

Not all swelling is harmless. Persistent swelling in one or both legs may signal an underlying health problem.

Heart failure can reduce the heart’s ability to pump blood efficiently, causing fluid to collect in the legs and feet. Kidney disease may prevent the body from removing extra fluid properly. Liver disease can also affect fluid balance and circulation.

A blood clot, especially if swelling happens suddenly in only one leg, can become dangerous and requires immediate medical attention. Signs such as redness, warmth, pain, or shortness of breath should never be ignored.

Varicose veins are another common cause. Damaged veins struggle to move blood back toward the heart, leading to swelling, aching, and heaviness in the legs.