The sinuses of scuba divers get a real workout, both during the descent to the depths and while returning to the surface. Like flight attendants, scuba divers must learn how to equalize pressure in their sinuses as they experience rapid changes in water and air pressure. If the sinuses are blocked by inflammation, divers can experience serious sinus pain, a bloody nose or worse.
You've probably heard of "the bends" or decompression sickness caused by a rapid ascent from a deep dive. Far less dangerous, but still painful, is "the squeeze," the diving world's nickname for barotrauma.
When a scuba diver descends, air should move freely through the sinuses, equalizing their internal pressure. But if there's a blockage, the air inside the sinus will contract in volume or get "squeezed." The squeeze pulls on the sinus walls, drawing out mucus, tissue and blood that partially fills the sinus cavity. If the loosened mucus and blood don't drain during ascent (causing a messy bloody nose), it could fester in the blocked sinus, attracting more bacteria and viruses.
The opposite problem happens if a diver's sinus gets blocked on ascent. The air will expand in the blocked passage, putting increased pressure on the sinus walls, which usually results in nothing more than a bad headache but could rupture the sinus wall in severe cases.
Sinus Congestion Tips
Here is some information to help you with sinus congestion.