What is reverse block in diving?

In diving, a reverse block occurs specifically during ascent when an air space, such as those in the sinuses or ears, becomes blocked due to a rapid decrease in pressure. As a diver ascends, the surrounding water pressure decreases, resulting in the expansion of air within the body. If this air cannot escape properly due to a blockage, it can lead to discomfort or injury.

Understanding the mechanics of pressure changes is crucial for divers. During ascent, the expanding air must be able to equalize; otherwise, it may cause pain or damage to the tissues. This makes the awareness of reverse block important for safe diving practices and pressure management.