Swelling is common during air travel Dependent edema ? the official name for leg and ankle swelling during air travel ? is common and typically harmless. The swelling is a combination of inactivity paired with the force of gravity pulling the fluids in your body toward earth.

Swelling during air travel, known as gravitational edema, is primarily caused by prolonged inactivity in a pressurized environment. When you sit for hours, the muscles in your legs aren't contracting to help pump blood and fluids back up to your heart. Gravity causes these fluids to pool in your lower extremities, leading to swollen feet and ankles. This is exacerbated by low cabin pressure (equivalent to being at 6,000–8,000 feet) and low humidity, which can cause your body to retain salt and water as a defensive measure. To combat this, experts recommend staying hydrated, avoiding salty "airplane snacks," and performing small leg exercises while seated. For those prone to significant swelling, wearing compression stockings is a highly effective way to apply pressure to the lower legs and encourage better circulation, reducing both discomfort and the risk of blood clots (DVT).