Methods and systems for using fibrosis biomarkers associated with a prolonged period of physical inactivity are provided. Also provided is a method of reducing the effect of prolonged physical inactivity on the development of fibrosis in a subject who is experiencing or is expected to experience prolonged physical inactivity in the near future by administering a therapeutically effective amount of a leucine metabolite (e.g., β-hydroxy-β-methylbutyric acid (HMB)) to the subject.
