Subjects with cystic fibrosis may be at increased risk of rhabdomyolysis during exercise, considering their propensity for dehydration and hyponatremia by sodium loss via sweat through a defective chloride ion transport channel, the CF transmembrane conductance regulator (CFTR) [73]; in a recent study, CFTR mutations were found not to be associated with the development of EAH [74]. This evidence concerns the gene CFTR and cystic fibrosis.