Muscle weakness and fatigue are actually two different conditions, although they can be caused by similar problems in some cases. There are a large number of potential causes of these symptoms, including disease, a muscle pull or tear, and overuse. A lack of certain minerals in the body, muscle wastage due to lack of use, and nervous system conditions may also lead to these problems. In some cases, muscle fatigue may simply be caused by insufficient sleep or exhaustion, although long-term symptoms may be a sign of something more serious.
Weakness occurs when the muscle isn’t able to provide its normal strength. This commonly occurs, for example, after a long workout in which the muscle becomes sore or tired for a period of time. This usually goes away naturally once the muscle has had time to recover.
True muscle weakness, where the muscle becomes permanently weak, is a more serious condition. If a muscle gets gradually weaker over time, this can be a sign of a number of health problems, including an impairment in the nervous system that affects the signals to the muscle, diseases such as celiac disease, and conditions such as fibromyalgia. In most cases, a gradual weakening of a muscle that’s being regularly used is cause for a visit to a medical professional for an evaluation.
Muscle weakness and fatigue, although similar, have noticeably different symptoms. Fatigue is when the muscles feel tired or lack energy. This can be caused by the person being overworked, not getting enough sleep, or general health problems, such as the common cold. Usually, fatigue will disappear when the problem is rectified. If it doesn’t get better within a couple of weeks, however, the individual should see a healthcare professional.
Some of the most serious causes of muscle problems include a disease that affects the liver or kidneys, diabetes, or heart failure. Any condition that limits the blood flow to the muscles can cause a feeling of weakness. Issues with the thyroid are also known to cause weakness and fatigue.
Both chronic fatigue syndrome and fibromyalgia can cause these types of symptoms. These conditions can be difficult to diagnose, so the weakness may be present for a long time before its cause is determined.