DISCUSSION
sarcopenia, muscle loss
INFLAMMATION, DNA DAMAGE, SARCOPENIA, CHRONIC DISEASES, CHRONIC INFLAMMATION
The preservation of muscle structure and function with aging is associated with healthy longevity and independence. The only intervention in humans proven to maintain muscle structure and function with aging is exercise (Egan & Zierath, Recent studies suggest that CR‐driven life extension is mediated by preserving the robustness and stability of the circadian rhythm, directly implicated in aging and age‐related chronic diseases (Eckel‐Mahan, KLF15 and KLF9 are two circadian clock transcription factors regulated by FOXO, a key metabolic regulator in the skeletal muscle (Kasai et al., CR improves mitochondrial function and biogenesis leading to the attenuation of age‐related declines in mitochondrial function in skeletal muscle (Civitarese et al., Autophagy and mitophagy remove toxic proteins and dysfunctional organelles, a mechanism essential for maintaining muscle health and preventing muscle loss and sarcopenia (Bagherniya et al., In differential gene expression analysis, the top CR‐associated overexpressed gene was Calorie restriction may modulate stress pathways in response to DNA damage (Ke et al., CR lowers chronic inflammation (Mattison et al., Several lines of evidence suggest that the spliceosome functionality and alternative pre‐mRNA splicing are necessary for the effect of CR on longevity (Heintz et al., In conclusion, our study contributes to the knowledge about the mechanisms of the health benefits of CR by elucidating a widespread skeletal muscle transcriptional impact of a moderate and humanly attainable CR intervention over a 2‐year period that mediates, at least in part, the preservation of muscle function. The biological mechanisms identified are the same as those affected by CR in animal models: the Sirtuin pathway, promotion of mitochondrial biogenesis and mitochondrial health, enhancement of autophagy and circadian rhythm, reduction of inflammation, and upregulation of alternative splicing. We used state‐of‐the‐art RNA‐Seq technology, with a depth (387–618 million paired reads) greater than any other previous studies of muscle in humans. Because of the data quality, rank‐based GSEA analysis was employed to leverage all the available information. Through DGE and GSEA analyses, several genes were identified that have not been previously discussed in the context of muscle effects of CR (Table 