Fatigue.

We all feel exhausted sometimes, whether it’s after a long week, a sleepless night, or a tough workout. But if you're feeling tired all the time—even after a...

Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME), causes overwhelming fatigue that is not improved by sleep or rest. CFS is sometimes also called systemic exertion intolerance...

If you’ve ever worked out vigorously, you’ve probably experienced muscle fatigue. As your exercise session progresses, actions you were once able to perform powerfully can suddenly become weaker...