Ear clearing

People who do intense weight lifting, such as squats, may experience sudden conductive hearing loss due to air pressure building up inside the ear.

[2] Diving is proscribed when a eustachian tube is congested or blocked, such as can occur with the common cold, as this may cause what is known as a reverse block, whereby descent is uninhibited as the Valsalva maneuver may still clear the eustachian tubes temporarily by force, but during ascent a blockage may stop the air in the middle ear (which is now at depth pressure) from escaping as the diver ascends.

[14] Nasal congestion may affect the sinus openings and the eustachian tubes and may lead to difficulty or inability to clear the ears.

[2] Because of the potential for side effects of the valsalva maneuver, scuba divers and free-divers may train to exercise the muscles that open the Eustachian tubes in a gentler manner.

The French underwater association (Fédération Française d'Études et de Sports Sous-Marins) has produced a series of exercises using the tongue and soft palate to assist a diver in clearing their ears by these techniques.

Those that are borderline on learning this voluntary control first discover this via yawning or swallowing or other means; which after practice can be done deliberately without force even when there are no pressure issues involved.