Which of the following is NOT a physical sign of fatigue?

In the context of fatigue, it is essential to identify the signs that typically indicate a lack of energy or decreased alertness. Increased energy levels stand out as an antithesis to the other options listed, which all accurately reflect common physical manifestations of fatigue.

Yawning, for example, is a well-documented response that often indicates drowsiness or a need for rest, signaling that the body is fatigued or not adequately refreshed. Similarly, sleepiness is a direct symptom that suggests an individual lacks sufficient rest and is too tired to maintain optimal functioning. Irritability can also be associated with fatigue, as a decrease in energy levels can affect mood and behavior, leading to feelings of frustration or annoyance.

In contrast, increased energy levels suggest a state of alertness and vitality, which is the opposite of fatigue. Therefore, recognizing the signs of fatigue is crucial in understanding how it impacts performance and behavior. This distinction highlights why recognizing increased energy levels is not a sign of fatigue; it actually indicates the opposite state of being refreshed and alert.