What should a diver do to equalize their ears during descent?

To equalize their ears during descent, a diver should perform the Valsalva maneuver, swallow, or gently blow against pinched nostrils. These techniques apply pressure to the Eustachian tubes, allowing air to flow from the throat into the middle ear. This action equalizes the pressure inside the ears with the increasing pressure from the surrounding water as the diver descends. It is essential to equalize early and often during descent to prevent discomfort and potential injury to the eardrum.

Other methods such as simply taking deep breaths or allowing pressure to resolve naturally are inadequate because they do not directly affect the pressure in the ears. Ignoring ear pressure until surfacing can lead to serious problems, including barotrauma, which can cause damage to the ear structure due to unrelieved pressure. Therefore, using proper equalization techniques is crucial for safe diving.