Which of the following is a common sign of stress in a diver?

Increased breathing rate is a common sign of stress in a diver. When individuals experience stress, there is often a physiological response that leads to a heightened breathing rate. This reaction is part of the body's fight-or-flight response, where increased oxygen intake is prepared for potential physical exertion or escape. In the underwater environment, an increase in respiratory rate can reflect anxiety, panic, or physical distress, indicating that the diver may not be managing the situation effectively.

The other options present behaviors that are generally associated with calmness and competency while diving. Increased buoyancy control, calm breathing, and effective communication all suggest that a diver is managing their stress or anxiety levels appropriately. In contrast, an increase in breathing rate typically signals that the diver is experiencing some level of distress or is overwhelmed, making it a key indicator for dive instructors and companions to monitor. Recognizing such signs is crucial for ensuring the safety and well-being of the diver in challenging situations.