Why do ankles swell? How can you prevent it?

Part 1 of 2

If your ankles seem to puff up by evening, it’s more than just an uncomfortable nuisance—it could be a sign something deeper is going on inside your body.

According to experts at the Cleveland Clinic and Harvard Medical School, swollen ankles—also known as peripheral edema—may be linked to anything from minor lifestyle habits to serious health conditions. Understanding the cause is essential for proper care and prevention.

What Is Edema—and Why Does It Target the Ankles?

Ankle swelling is usually caused by fluid building up in the body’s soft tissues, a condition known as edema. It often affects the feet and ankles due to gravity, especially if you’ve spent the day sitting or standing. Circulation slows, and the body struggles to drain fluids efficiently through the lymphatic system.

“Swelling in the ankles isn’t always dangerous,” says Harvard Health, “but if it’s frequent or painful, it could indicate a more serious problem.”

Common Reasons for Swollen Ankles

Sitting or Standing Too Long
Lack of movement—especially during flights or desk work—prevents blood from flowing back to the heart, allowing it to pool in the legs.

Water Retention
High salt intake, dehydration, or hormonal changes can lead to fluid buildup, especially in the ankles by day’s end.

Poor Circulation
Conditions like chronic venous insufficiency, where vein valves fail to work properly, cause swelling due to blood pooling in the legs.

Heart or Kidney Problems
Bilateral swelling, paired with symptoms like fatigue or rapid weight gain, may be an early sign of congestive heart failure or kidney dysfunction.

Medications
Drugs like corticosteroids, antidepressants, hormone therapies, or some blood pressure medications may cause edema. Check with your doctor if you notice swelling after starting a new medication.