Everyday tiredness from a busy life usually improves with rest, better sleep, and lifestyle changes. Fatigue becomes a medical concern when it is persistent, unexplained, and interferes with daily function, or when it appears alongside other symptoms. Red flags include unintentional weight loss, drenching night sweats, breathlessness, chest pain, fainting, swollen glands that do not settle, or very heavy menstrual bleeding.
These features can point to conditions such as anemia, thyroid disease, diabetes, heart or lung problems, sleep disorders, depression, or, less commonly, more serious illness. A doctor can take a history, examine you, and arrange basic tests to find or exclude a cause.
If fatigue comes on suddenly with chest pain, severe breathlessness, or confusion, treat it as an emergency and call your local emergency number. Otherwise, book a routine appointment if tiredness lasts beyond a few weeks. Informational only.