Which of the following describes the condition of Chronic Fatigue Syndrome?

Chronic Fatigue Syndrome (CFS) is characterized primarily by profound fatigue that is not improved by rest and significantly impairs daily functioning. Individuals with CFS often experience debilitating tiredness that lasts for six months or more, along with other symptoms such as sleep disturbances, cognitive difficulties, and muscle pain. This fatigue is not just a result of normal physical exertion; it can be exacerbated by physical or mental activity, and it is disproportionate to any previous activity level.

Other conditions listed do not accurately capture the essence of CFS. For instance, while frequent migraines might be a symptom some individuals experience, they do not define the syndrome itself. Similarly, temporary feelings of tiredness are not reflective of the chronic and debilitating nature of CFS. Muscle-related disorders may involve pain or weakness, but they lack the systemic and multifaceted impact that characterizes Chronic Fatigue Syndrome. Therefore, the defining feature of CFS is a persistent lack of energy that disrupts the individual's ability to function in everyday life.