Chronic fatigue syndrome (CFS) is characterized by what condition?

Chronic fatigue syndrome (CFS) is primarily characterized by persistent fatigue that is not alleviated by rest and is often worsened by physical or mental activity. This fatigue is debilitating and can significantly impair daily functioning. While individuals with CFS may also experience a variety of other symptoms such as muscle pain, headaches, sleep disturbances, and cognitive difficulties, the defining feature of the syndrome is the long-lasting and profound fatigue that persists for six months or longer. This persistent fatigue is distinctive and sets CFS apart from other conditions that might cause fatigue, making it the most accurate representation of the syndrome's primary condition.