Which option best defines fatigue in this context?

• A. A brief feeling of tiredness after exercise
• B. Increased energy during activity
• C. Fatigue is unrelated to performance
• D. Overwhelming sustained feeling of exhaustion and decreased capacity to complete physical and mental work

Answer: (D)

Fatigue in this context describes an overwhelming, sustained sense of exhaustion that reduces both physical and mental capacity to continue work. It goes beyond a quick tiredness after exercise and reflects a drop in performance, not just a feeling of being worn out. It also means the effect is ongoing and limits how hard you can sustain effort, rather than giving you more energy. The other options fail because brief post-exercise tiredness is not as severe or long-lasting, increased energy is the opposite, and fatigue's link to performance is essential, not absent.