Almost one in five adults is affected, yet we do not fully understand why we are tired.

Fatigue affects nearly one in five adults, yet its causes remain poorly understood. Chronic fatigue can stem from various diseases and medications, complicating its definition. Researchers struggle to pinpoint fatigue's nature, as it overlaps with other conditions like depression and motivational disorders. Anna Kuppuswamy, a neuroscientist, emphasizes that fatigue is a subjective experience, not easily measurable or linked to specific physical or psychological factors. Current theories suggest that fatigue may involve complex interactions within the nervous system, similar to pain responses. Understanding fatigue requires further research to clarify its mechanisms and impacts.