What should you know about alternobaric vertigo?

Each middle ear connects to the back of the nose through a eustachian tube. If one tube equalises pressure more slowly than the other, the inner-ear balance systems receive mismatched signals. This can cause sudden spinning, nausea, disorientation, or a feeling of tilting. A cold, nasal congestion, allergy symptoms, or difficulty equalising can make the pressure mismatch more likely. The sensation often settles when ear pressure becomes even, but persistent vertigo may have another cause.

Stop changing depth or altitude if it is safe to do so, hold onto a stable reference, and allow time for pressure to equalise. A diver should signal their buddy and avoid a rapid ascent or descent. Use only the gentle equalisation method you were trained to perform; forceful attempts can injure the ear. Do not continue diving while dizzy, congested, or unable to equalise. During a flight, swallowing, yawning, or sipping water may help the eustachian tubes open.

Get urgent medical help if vertigo after diving occurs with weakness, numbness, trouble speaking, severe imbalance, confusion, loss of consciousness, breathing difficulty, or chest pain. These symptoms need assessment for diving-related illness or another neurological problem. Arrange prompt medical review if spinning continues after pressure has normalised, repeatedly returns with altitude changes, or comes with severe ear pain, sudden hearing change, ringing, fluid, or blood from the ear. Avoid another dive until persistent or recurrent symptoms have been assessed.

Ask whether congestion, eustachian tube dysfunction, an ear injury, or another balance disorder could explain the episode. Describe exactly when the spinning began, whether you were ascending or descending, which ear felt blocked, how long symptoms lasted, and whether hearing changed. If you dive, ask what recovery signs and ear findings should guide a safe return to diving.