why do my muscles always feel tired
You may feel weak and tired, or your muscles may be sore. These sensations usually go away within a few days. In rare cases, generalized muscle weakness may be caused by another health problem, such as: 1  A problem with the minerals (electrolytes) found naturally in the body, such as low levels of potassium or sodium. Fatigue is a feeling of tiredness or exhaustion or a need to rest because of lack of energy or strength. 2  Fatigue may result from overwork, poor sleep, worry, boredom, or lack of exercise.