Swollen legs (also called leg edema) can happen for many reasons—some harmless, some serious. It occurs when fluid builds up in the tissues of the lower limbs.
Here are the common causes you should know about and not ignore:
🟢 Common (often less serious) causes
1. Long sitting or standing
- Fluid collects in the lower legs due to gravity
- Common in travel, desk jobs, or long standing hours
2. High salt intake
- Too much salt causes the body to retain water
- Often worsens swelling at the end of the day
3. Heat and dehydration
- Hot weather causes blood vessels to expand
- Fluid can leak into surrounding tissues
4. Mild injury or strain
- Sprains or muscle injuries can cause localized swelling
🟡 Medical causes that need attention
5. Vein problems (very common)
Weak vein valves can cause blood to pool in the legs, leading to swelling.
Related condition: Varicose veins
Signs:
- Swelling worse at the end of the day
- Heaviness or aching legs
- Visible enlarged veins
6. Heart problems
When the heart doesn’t pump efficiently, fluid can back up into the legs.
Related condition: Heart failure
Signs:
- Swelling in both legs
- Shortness of breath
- Fatigue
- Worse when lying flat
7. Kidney disease
Kidneys may not remove excess fluid properly.
Signs:
- Swelling around eyes and legs
- Foamy urine
- Fatigue or reduced urination
8. Liver disease
Low protein production causes fluid leakage into tissues.
Signs:
- Abdominal swelling
- Easy bruising
- Yellowing of skin or eyes
9. Blood clots (urgent condition)
A clot can block blood flow in a leg vein.
Related condition: Deep vein thrombosis
Warning signs:
- Swelling in one leg only
- Pain or tenderness
- Warmth and redness
