Which of the following is a common characteristic of fatigue?

Fatigue is commonly associated with a lack of energy, which is why this choice is the correct answer. When individuals experience fatigue, they often find it challenging to perform tasks, maintain concentration, or engage in activities they typically would participate in with vigor. The state of fatigue can manifest as physical tiredness, mental exhaustion, or emotional depletion, all of which contribute to a noticeable decrease in overall energy levels.

In contrast, other characteristics such as increased productivity, enhanced focus and alertness, and improved social engagement would be contradictory to the experience of fatigue. Typically, when someone is fatigued, their productivity diminishes rather than increases, their attention may wane rather than sharpen, and they might withdraw from social interactions instead of engaging more. This makes the recognition of lack of energy as the key characteristic of fatigue essential in various contexts, especially in assessing fitness for duty and ensuring safety in performance-driven environments.