The colloquial use of the term by Trump, the White House, and U.S. governmental departments has prompted criticism.

Doctors discuss how common the condition is, why it happens — and whether Trump's symptoms align with his diagnosis.

Here's what to know about the condition, whose likelihood increases with age: Chronic venous insufficiency occurs when veins in the legs are damaged and don’t work properly. The veins are supposed to keep blood flowing back to the heart and the valves in the veins are supposed to prevent backward flow.