ATF3 and chronic obstructive pulmonary disease: Interestingly, when exploring the effects of exercise in skeletal muscle gene expression [86,87], while exercise training contribute to “normalise” the expression of genes related with energy production and oxidative capacity of the muscle, several genes found up-regulated in our COPD population were not modified (“normalized”) by exercise training (including GADD45A, NNMT, ANKRD1, ATF3 and SLC38A1) suggesting that the increased expression of these genes in our population of COPDL is not related to physical activity levels since this should produce the opposite effect.