Muscle fatigue is caused by muscle overload, meaning when physical effort exceeds the normal level. Symptoms of muscle fatigue include muscle pain, weakness, and decreased physical performance during exercise.
Muscle fatigue is common after periods of intense physical activity and not enough rest between workouts. It can also occur as a consequence of mineral deficiencies or conditions like uncontrolled diabetes and kidney disease.
It is important to see a healthcare provider for muscle fatigue lasting more than 2 days or accompanied by other symptoms. In these cases, tests can be ordered to help identify a cause and inform the best treatment.
Common symptoms
The main symptoms of muscle fatigue are:
- Difficulty performing day-to-day functions like grasping objects, holding your arms out straight, walking, or standing for long periods of time;
- Muscle pain;
- Muscle weakness;
- Decreased exercise performance.
The intensity of symptoms can vary from person to person based on the cause. People who are experiencing constant muscle fatigue should make an appointment with their healthcare provider.
Main causes
Muscle fatigue can be a consequence of:
1. Intense physical activity
Intense physical activity can overload the muscles and lead to muscle fatigue, especially in those who are not used to working out, are trying a new form of exercise, or have not rested for an adequate amount of time between workouts.
What to do: It is important to work with an exercise physiologist or certified personal trainer to help prevent muscle overload and to build in rest days between workouts to allow for muscle recovery. Other tips for combating muscle fatigue following exercise include:
- Applying warm compresses to dilate the blood vessels and increase blood flow to the area, helping to relax the muscles and reduce pain;
- Taking a warm bath to help relax the muscles and relieve muscle pain;
- Massaging the area using an anti-inflammatory ointment or spray to promote relaxation of the muscles and relieve pain.
Warming up prior to working out and stretching afterwards can also help prevent muscle fatigue and boost recovery.
2. Mineral deficiencies
One of the main causes of muscle fatigue, especially frequent muscle fatigue, is a deficiency in important minerals in the body, such as potassium, magnesium, or calcium. These minerals are essential for muscle function and allow for contraction and relaxation of the muscle fibers. Mineral deficiencies can make it more difficult for the muscles to function, leading to fatigue.
What to do: In the case of mineral deficiencies, it is necessary to consume foods high in calcium, potassium, and magnesium and consult your primary care provider if the problem persists. Your provider may order blood tests to confirm the diagnosis and prescribe nutritional supplements if necessary.
3. Anemia
Anemia is another common cause of muscle fatigue due to a lack of red blood cells responsible for transporting oxygen to the muscles, which is necessary for the muscles to function.
Anemia typically develops gradually, meaning some anemia symptoms like muscle fatigue, tiredness, and shortness of breath may show up even before a diagnosis is made.
What to do: Consult your primary care provider if you are concerned you may be anemic. Blood tests can confirm the diagnosis. While iron pills are often prescribed for anemia, treatment will vary based on the type of anemia.
4. Diabetes
Diabetes is another possible cause of muscle fatigue, typically in the case of constant muscle fatigue. This is because diabetes causes an increase in blood sugar levels that can affect nerve sensitivity and cause the muscle fibers innervated by the affected nerves to become weaker or cease to function, leading to muscle fatigue and a loss of muscle strength.
What to do: Muscle fatigue is more common in people with uncontrolled diabetes. It is essential for people with diabetes to adhere to an individualized treatment plan as outlined by their healthcare provider. Diabetes that is not being adequately treated may require a consultation with an endocrinologist to reevaluate the treatment plan and make any necessary changes.
5. Heart problems
Certain heart problems, particularly cardiac insufficiency, can decrease the amount of oxygenated blood delivered to the muscles and throughout the rest of the body, resulting in symptoms like excessive tiredness even without exercise and frequent shortness of breath.
What to do: A primary care provider or cardiologist should be consulted if there are any concerns for heart problems. Exams like an electrocardiogram (ECG) can be ordered to test whether the heart is functioning properly.
6. Kidney disease
Kidneys that are not functioning well can cause mineral imbalances in the body. Abnormal levels of minerals like calcium, magnesium, or potassium can cause the muscles to stop working and lead to a significant loss of muscle strength and general fatigue.
What to do: People with a family history of kidney disease or who suspect they may have kidney disease should talk to their primary care provider or a nephrologist (kidney specialist) in order to identify any problems and arrange for the most appropriate treatment.