MTOR and chronic obstructive pulmonary disease: Resistance and endurance exercises can also significantly increase the IGF-1 levels in COPD muscles; the latter upregulated myogenin mRNAs, Akt phosphorylation, glycogen synthase kinase-3β (GSK-3β), and mammalian target of rapamycin (mTOR) while decreasing the expression of forkhead box O1 to promote muscle hypertrophy and enhance muscle quality [87,88].