What are common signs indicating overexertion during physical activity?

The correct choice highlights the common signs of overexertion during physical activity, which include pain, fatigue, and difficulty breathing. These symptoms indicate that the body is under stress and struggling to meet the demands being placed on it. Pain can signal that a certain level of physical strain is excessive, while fatigue reflects a depletion of energy and a need for recovery. Difficulty breathing, especially if it is exaggerated or persists despite rest, is a clear indication that the body is not adequately handling the intensity of the workout, suggesting that the individual may be pushing beyond their physical limits.

In contrast, the other options represent signs of positive physical responses rather than indicators of overexertion. Increased appetite and energy suggest recovery and adaptation to physical stress rather than excessive strain. Improved mood and sleep can be a result of regular exercise and are generally associated with a balanced fitness routine. Similarly, enhanced flexibility and stamina indicate progress in fitness levels, showing that the body is adapting well rather than signaling overexertion.