What should divers do if they experience difficulty breathing while ascending?

When a diver experiences difficulty breathing while ascending, the best course of action is to continue breathing normally and ascend slowly. This approach is essential because maintaining a steady flow of air helps to ensure that the diver's lungs are not holding onto excess gas, which could lead to serious complications such as lung overexpansion injury.

Ascend slowly while breathing normally allows the diver to both regulate buoyancy and manage any potential gas exchange issues that may be occurring in the lungs. Inhaling and exhaling regularly assists in avoiding the risks associated with improper ascent rates and helps to expel accumulated carbon dioxide effectively.

The other options suggest actions that are contrary to safe diving practices. Speeding up the ascent could lead to rapid decompression and increased risk of decompression sickness. Holding one’s breath during ascent can cause lung expansion injuries due to the increase in pressure which reduces as the diver rises. Alerting surface support by flaring the arms may not effectively address the immediate respiratory issue and can distract from the essential task of maintaining normal breathing and safe ascent.