The AMPD1 gene gives your muscle cells the ability to quickly use energy during time of exertion. Variants of this gene can impact how efficiently this process occurs. Individuals with the inefficient variant (called Adenosine monophosphate deaminase 1 deficiency) may fatigue faster and experience muscle cramping during or after strenuous exercise.
If you have a certain variant of this gene, it may put you at risk for muscle cramping, possibly due to a deficiency of Adenosine Monophosphate Deaminase, the enzyme responsible for catalyzing an energy producing reaction that reduces Adenosine Monophosphate to Inosine Monophosphate. This reaction occurs within skeletal muscle cells as fatigue begins, due to the exhaustion of the Phosphocreatine System.
The inability to breakdown AMP and clear AMP causes it to spill into the blood outside the muscle cell. In turn, the cell is starved of the key by-product D-ribose. D-ribose is a simple sugar that serves as a quick source of energy for exercising muscle. Supplementation of this sugar has shown to mitigate some of the metabolic dysfunction, undue fatigue, and muscle cramping associated with the lack of D-ribose.
D-ribose must be taken constantly in order to sustain sufficient blood sugar levels and uptake by exercising muscle — the half life is very short. It is recommended that while exercising, one consumes 0.1-0.15 mg/kg per hour. Less will not be effective, and more can cause gastro-intestinal discomfort. D-ribose doesn't have a strong taste, and mixes well with water. Consider sipping on this during your workout if you are experiencing bouts of muscle cramping or localized premature muscle fatigue.
Find out which variant of the AMPD1 gene you have and get more expert recommendations from Dr. Kelly Starrett and his MobilityWOD team on what you can do if your genetics put you at an increased risk of muscle cramping.