Fig. 8. Graphical representation of the study and main results.

This study mainly focused on investigating molecular changes in skeletal muscle-associated and circadian rhythm-associated pathways such as metabolism, myonuclei, myogenesis (left side; symbols) in healthy skeletal muscle, and altered conditions (i.e., clock manipulation, spaceflight, bed rest, aging, exercise, fasting) from left to right order. Core-clock genes and skeletal muscle-associated genes depicted similar patterns (upregulation: yellow; downregulation: blue) in gene expression profiles due to spaceflight and aging on Earth (e.g. Rorc, Atf4; right side). While exercise or fasting conditions showed opposite gene expression patterns in the same genes.