Which of the following is NOT a cause of fatigue?

Consistent exercise and physical activity do not cause fatigue; in fact, they can help improve energy levels and overall well-being. Regular physical activity is known to enhance stamina, strengthen muscles, and boost cardiovascular health, which can lead to increased energy rather than feelings of exhaustion. It can also improve sleep quality, further reducing fatigue.

Conversely, lack of sleep, extreme temperatures (whether hot or cold), and bright sunlight can contribute to feelings of fatigue. Insufficient sleep restricts the body’s ability to recover and rejuvenate, leading to increased tiredness. Similarly, extreme hot or cold weather can place extra demands on the body, potentially causing fatigue as it works harder to maintain a stable internal environment. Bright sunlight, particularly if it leads to discomfort or heat exhaustion, can also contribute to feelings of lethargy. Thus, while lack of sleep, extreme weather, and bright sunlight can all be stressors leading to fatigue, consistent exercise is generally beneficial for energy levels.