Which of the following is considered a physical cause of stress while diving?

Lack of fitness is identified as a physical cause of stress while diving because physical conditioning plays a crucial role in a diver's ability to manage underwater challenges. A diver who is not physically fit may struggle with the demands of diving, including managing equipment, regulating their buoyancy, or swimming against currents. This can lead to increased fatigue and difficulty, which can elevate stress levels during a dive.

On the other hand, overconfidence, while it may lead to dangerous behaviors and decisions, is more related to psychological stress rather than a physical limitation. Adequate hydration, although essential for overall health and performance, does not directly cause stress; in fact, it is a preventative measure against physical stress. Clear communication is also not a physical cause of stress but rather a practice that enhances safety and reduces misunderstandings among divers, contributing to a stress-free diving experience.