Foot swelling during air travel: A concern?

What causes leg and foot swelling during air travel?

- Phil / California

Answer

Leg and foot swelling during air travel is common and typically harmless. The most likely culprit is inactivity during a flight. Sitting with your feet on the floor for a long period causes blood to pool in your leg veins. If you get up and walk around, your leg muscles contract and compress the veins, forcing blood back to your heart.

The position of your legs when seated also increases pressure in your leg veins. This contributes to foot swelling by causing fluid to leave the blood and move into the surrounding soft tissues. Another cause of swelling in the ankles and feet may be certain medications, such as calcium channel blockers.

You can usually relieve swelling during and after a flight by:

• Elevating your feet and legs
• Getting up and walking once an hour
• Rotating your ankles while seated

Foot swelling isn't a serious problem if it lasts only a short time. But excessive swelling that persists for several hours after you resume activity may be due to a more serious condition, such as a blood clot in the leg (deep vein thrombosis, or DVT) — especially if the swelling occurs in only one leg and is accompanied by leg pain. These signs and symptoms require prompt medical attention.

On flights lasting six hours or more, consider taking these additional precautions to reduce the risk of DVT:

• Avoid wearing tight clothing around your waist.
• Drink plenty of fluids to avoid dehydration.
• Stretch your calves every half hour.
• Avoid alcohol and sedatives, which promote immobility.

If you're at increased risk of blood clots, such as due to factor V Leiden, talk to your doctor before flying. He or she may recommend:

• Compression stockings
• Low-molecular-weight heparin given two to four hours before departure

Taking aspirin before a long flight isn't effective in reducing the risk of blood clots.

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