An important point of this pilot study is that CPET prior to an exercise training intervention in those with LC can uncover unexpected comorbidities attributed to LC symptoms (e.g., fatigue, dyspnea, exercise intolerance, PEM, etc.)We excluded participants with potential contraindications to exercise training, including myocarditis (troponin and BNP), autonomic insufficiency (NASA lean test), and serious comorbidities that might masquerade as LC symptoms (e.g., coronary artery disease, cardiac rate disturbances, metabolic disorders) by performing a CPET prior to exercise training. This evidence concerns the gene NPPB and metabolic disease.