MTHFR diet, MTHFR lifestyle, MTHFR mutation Fatigue: Causes and Management Fatigue refers to a feeling of tiredness or lack of energy. This is distinct from the feeling of being drowsy or sleepy. Motivation and mental energy are often impaired in fatigue as well as phycial energy. Sleepiness can be a… Share with friends:Amy NeuzilFebruary 9, 2023