Which of the following is an early warning sign of stress while diving?

A rapid heartbeat is indeed seen as an early warning sign of stress while diving. When divers experience stress, their body often reacts by triggering the sympathetic nervous system, leading to physiological responses such as an elevated heart rate. This can serve as a signal that the diver is experiencing anxiety or discomfort, both of which can impair decision-making and affect overall safety underwater.

In contrast, increased awareness, calm breathing, and relaxed muscles are typically associated with a state of comfort and control. Increased awareness is often a sign of heightened alertness, which may not necessarily indicate stress but an adaptive response to the diving environment. Calm breathing suggests that the diver is relaxed and in control, whereas relaxed muscles imply a lack of tension, again a sign of ease rather than stress. Recognizing these early warning signs, such as a rapid heartbeat, is crucial for divers to manage stress effectively and maintain safety during the dive.