Also known as glycogen storage disease type V (GSD-V), is a rare genetic disorder that affects muscle metabolism. It is caused by a deficiency of the enzyme myophosphorylase, which is responsible for breaking down glycogen (the stored form of glucose) into glucose to provide energy to the muscles during exercise. In McArdle disease, the impaired breakdown of glycogen leads to a reduced ability to produce energy, resulting in muscle symptoms during physical activity.


The condition is inherited in an autosomal recessive manner, meaning that both copies of the gene responsible for myophosphorylase deficiency must be mutated for the disease to occur.


Symptoms of McArdle disease typically manifest during childhood or adolescence, although they can appear at any age. The most common symptoms include:

  1. Exercise intolerance: Individuals with McArdle disease experience muscle fatigue, pain, and cramps during exercise. This is due to the limited availability of glucose as an energy source for the muscles.
  2. Early muscle fatigue: The affected muscles tend to fatigue quickly, even with mild to moderate physical activity. This can lead to a reduced ability to participate in prolonged exercise or activities that require significant exertion.
  3. Myoglobinuria: In more severe cases, individuals with McArdle disease may develop myoglobinuria, which is the presence of myoglobin (a muscle protein) in the urine. This can cause the urine to become dark or reddish-brown after exercise.
  4. Muscle stiffness: Some individuals may experience muscle stiffness or "second wind" phenomenon, where symptoms improve after a brief rest period during exercise.


  • Exercise testing
  • Blood tests to measure enzyme levels
  • Genetic testing to identify the specific mutations in the PYGM gene.


 McArdle disease primarily focuses on avoiding activities that lead to muscle symptoms and the risk of myoglobinuria. This involves maintaining a balanced and controlled exercise program, including warm-up periods, pacing, and avoiding high-intensity or prolonged activities. Individuals with McArdle disease are advised to consume a diet that supports steady glucose levels and may need to consider alternative energy sources during exercise, such as low-intensity aerobic exercise or aerobic activities preceded by a carbohydrate-rich meal or snack.


  1. Gelsemium: Gelsemium is often considered for weakness, trembling, and a general feeling of heaviness and exhaustion. It may be useful in cases where there is associated anxiety or nervousness.
  2. Natrum Mur: Natrum Mur is used for symptoms of weakness, fatigue, and a desire for salt. It may be considered for individuals who experience emotional sensitivity or have a tendency to retain fluids.
  3. Phosphoric Acid: Phosphoric Acid is sometimes used for mental and physical exhaustion, weakness, and lack of vitality. It may be considered for individuals who experience apathy, indifference, or emotional grief.
  4. Argentum Nitricum: Argentum Nitricum is used for symptoms such as trembling, weakness, and anxiety. It may be considered for individuals who have a strong craving for sweets and experience digestive disturbances.
  5. Uranium Nitricum: Uranium Nitricum is sometimes used for symptoms associated with diabetes and low blood sugar. It may be considered for individuals who have increased thirst, frequent urination, and weakness.