Final answer:
The condition that involves excessive fatigue, often marked by physical aches and reduced mental alertness is called chronic fatigue syndrome (CFS).
Step-by-step explanation:
The condition that involves excessive fatigue, often marked by physical aches and reduced mental alertness is called chronic fatigue syndrome (CFS). CFS is a complex disorder characterized by extreme fatigue that can't be explained by any underlying medical condition. The fatigue can worsen with physical or mental activity and doesn't improve with rest. In addition to fatigue, CFS can also cause muscle pain, joint pain, headaches, difficulty concentrating, and sleep problems.
One possible cause of CFS is a malfunction in the immune system, although the exact cause is still unknown. Other factors that may contribute to the development of CFS include viral infections, hormonal imbalances, and psychological factors.
If you or someone you know is experiencing symptoms of extreme fatigue and reduced mental alertness, it is important to consult a healthcare professional for a proper diagnosis and appropriate treatment.