Which factor is NOT considered a cause of fatigue?

Fatigue can stem from various sources, and understanding these can help drivers maintain alertness and safety on the road. While physical labor can indeed contribute to fatigue, it is not typically classified as a direct cause of fatigue in the context of the choices provided.

Emotional stress can lead to mental fatigue, which can affect concentration and alertness. Poor sleep habits directly impact the quality and quantity of rest one gets, significantly impacting energy levels and alertness. Long driving hours are a well-known contributor to physical and mental fatigue, as prolonged periods of being behind the wheel can lead to exhaustion, reduced focus, and slower reaction times.

In contrast, physical labor, while it can be tiring, is not inherently considered a chronic cause of fatigue in the same way that the other factors are, especially when discussing driving and its implications for alertness and safety. Physical labor can also be balanced with adequate rest and recovery, mitigating its impact on overall fatigue levels.